Publications
2023 |
Wang, Wenhui; Erofeev, Ivan; He, Ya; Yang, Fangqi; Yan, Hongwei; Lu, Jiong; Mirsaidov, Utkur Direct Observation of Hollow Bimetallic Nanoparticle Formation through Galvanic Replacement and Etching Reactions Journal Article NANO LETTERS, 23 (23), pp. 10725-10730, 2023, ISSN: 1530-6984. @article{ISI:001125314300001, title = {Direct Observation of Hollow Bimetallic Nanoparticle Formation through Galvanic Replacement and Etching Reactions}, author = {Wenhui Wang and Ivan Erofeev and Ya He and Fangqi Yang and Hongwei Yan and Jiong Lu and Utkur Mirsaidov}, doi = {10.1021/acs.nanolett.3c02575}, times_cited = {0}, issn = {1530-6984}, year = {2023}, date = {2023-11-21}, journal = {NANO LETTERS}, volume = {23}, number = {23}, pages = {10725-10730}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Hollow bimetallic nanoparticles (NPs) formed from metal oxide NP templates are widely used catalysts for hydrogen evolution and CO2 reduction reactions. Despite their importance in catalysis, the details of how these NPs form on the NP templates remain unclear. Here, using in situ liquid-phase transmission electron microscopy (TEM) imaging, we describe the conversion of Cu2O template NPs to hollow PdCu NPs. Our observations show that a polycrystalline PdCu shell forms on the surface of the template via a galvanic replacement reaction while the template undergoes anisotropic etching. This study provides important insights into the synthesis of hollow metallic nanostructures from metal oxide templates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hollow bimetallic nanoparticles (NPs) formed from metal oxide NP templates are widely used catalysts for hydrogen evolution and CO2 reduction reactions. Despite their importance in catalysis, the details of how these NPs form on the NP templates remain unclear. Here, using in situ liquid-phase transmission electron microscopy (TEM) imaging, we describe the conversion of Cu2O template NPs to hollow PdCu NPs. Our observations show that a polycrystalline PdCu shell forms on the surface of the template via a galvanic replacement reaction while the template undergoes anisotropic etching. This study provides important insights into the synthesis of hollow metallic nanostructures from metal oxide templates. |
Subagyo, Riki; Maulida, Pramitha Y D; Kowal, Dominik; Hartati, Sri; Muslimawati, Rossyaila M; Zetra, Yulfi; Diguna, Lina J; Akhlus, Syafsir; Mahyuddin, Muhammad H; Zhang, Lei; Tang, Chi S; Diao, Caozheng; Wee, Andrew T S; Birowosuto, Muhammad D; Arramel, Andrivo; Rusydi, Andrivo; Kusumawati, Yuly Spectroscopic Evidence of Localized Small Polarons in Low-Dimensional Ionic Liquid Lead-Free Hybrid Perovskites Journal Article ACS APPLIED MATERIALS & INTERFACES, 15 (47), pp. 54677-54691, 2023, ISSN: 1944-8244. @article{ISI:001111123400001, title = {Spectroscopic Evidence of Localized Small Polarons in Low-Dimensional Ionic Liquid Lead-Free Hybrid Perovskites}, author = {Riki Subagyo and Pramitha Y D Maulida and Dominik Kowal and Sri Hartati and Rossyaila M Muslimawati and Yulfi Zetra and Lina J Diguna and Syafsir Akhlus and Muhammad H Mahyuddin and Lei Zhang and Chi S Tang and Caozheng Diao and Andrew T S Wee and Muhammad D Birowosuto and Andrivo Arramel and Andrivo Rusydi and Yuly Kusumawati}, doi = {10.1021/acsami.3c12889}, times_cited = {0}, issn = {1944-8244}, year = {2023}, date = {2023-11-15}, journal = {ACS APPLIED MATERIALS & INTERFACES}, volume = {15}, number = {47}, pages = {54677-54691}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Rational design is an important approach to consider in the development of low-dimensional hybrid organic-inorganic perovskites (HOIPs). In this study, 1-butyl-1-methyl pyrrolidinium (BMP), 1-(3-aminopropyl)imidazole (API), and 1-butyl-3-methyl imidazolium (BMI) serve as prototypical ionic liquid components in bismuth-based HOIPs. Element-sensitive X-ray absorption spectroscopy measurements of BMPBiBr4 and APIBiBr(5) reveal distinct resonant excitation profiles across the N K-edges, where contrasting peak shifts are observed. These 1D-HOIPs exhibit a large Stokes shift due to the small polaron contribution, as probed by photoluminescence spectroscopy at room temperature. Interestingly, the incorporation of a small fraction of tin (Sn) into the APIBiBr(5) (Sn/Bi mole ratio of 1:3) structure demonstrates a strong spectral weight transfer accompanied by a fast decay lifetime (2.6 ns). These phenomena are the direct result of Sn-substitution in APIBiBr(5), decreasing the small polaron effect. By changing the active ionic liquid, the electronic interactions and optical responses can be moderately tuned by alteration of their intermolecular interaction between the semiconducting inorganic layers and organic moieties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Rational design is an important approach to consider in the development of low-dimensional hybrid organic-inorganic perovskites (HOIPs). In this study, 1-butyl-1-methyl pyrrolidinium (BMP), 1-(3-aminopropyl)imidazole (API), and 1-butyl-3-methyl imidazolium (BMI) serve as prototypical ionic liquid components in bismuth-based HOIPs. Element-sensitive X-ray absorption spectroscopy measurements of BMPBiBr4 and APIBiBr(5) reveal distinct resonant excitation profiles across the N K-edges, where contrasting peak shifts are observed. These 1D-HOIPs exhibit a large Stokes shift due to the small polaron contribution, as probed by photoluminescence spectroscopy at room temperature. Interestingly, the incorporation of a small fraction of tin (Sn) into the APIBiBr(5) (Sn/Bi mole ratio of 1:3) structure demonstrates a strong spectral weight transfer accompanied by a fast decay lifetime (2.6 ns). These phenomena are the direct result of Sn-substitution in APIBiBr(5), decreasing the small polaron effect. By changing the active ionic liquid, the electronic interactions and optical responses can be moderately tuned by alteration of their intermolecular interaction between the semiconducting inorganic layers and organic moieties. |
Noviyanto, Alfian; Amalia, Ratih; Maulida, Pramitha Yuniar Diah; Dioktyanto, Mudzakkir; Arrosyid, Bagas Haqi; Aryanto, Didik; Zhang, Lei; Wee, Andrew T S; Arramel, Anomalous Temperature-Induced Particle Size Reduction in Manganese Oxide Nanoparticles Journal Article ACS OMEGA, 8 (47), pp. 45152-45162, 2023, ISSN: 2470-1343. @article{ISI:001110569800001, title = {Anomalous Temperature-Induced Particle Size Reduction in Manganese Oxide Nanoparticles}, author = {Alfian Noviyanto and Ratih Amalia and Pramitha Yuniar Diah Maulida and Mudzakkir Dioktyanto and Bagas Haqi Arrosyid and Didik Aryanto and Lei Zhang and Andrew T S Wee and Arramel}, doi = {10.1021/acsomega.3c08012}, times_cited = {0}, issn = {2470-1343}, year = {2023}, date = {2023-11-13}, journal = {ACS OMEGA}, volume = {8}, number = {47}, pages = {45152-45162}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The intricate role of temperature in the structure-property relationship of manganese oxide nanoparticles (Mn3O4 NPs) remains an open question. In this study, we successfully synthesized Mn3O4 NPs using the hydrothermal method with two differing temperatures, namely, 90 and 150 degrees C. Interestingly, a smaller average particle size is found when Mn3O4 NPs are synthesized at 150 degrees C compared to 90 degrees C, corresponding to 46.54 and 63.37 nm, respectively. This was confirmed by the time variation of temperature setting of 150 degrees C where the size evolution was insignificant, indicating a competing effect of nucleation and growth particles. Under varying NaOH concentrations (2-6 M) at 150 degrees C, a reduction in the particle size is found at the highest NaOH concentration (6 M). The particle grows slightly, indicating that the growth state is dominant compared to the nucleation state at low concentrations of NaOH. This finding implies that the high nucleation rate originates from the excessive monomer supply in the high-temperature reaction. In terms of crystallinity order, the structural arrangement of Mn3O4 NPs (150 degrees C) is largely decreased; this is likely due to a facile redox shift to the higher oxidation state of manganese. In addition, the higher ratio of adsorbed oxygen and lattice oxygen in Mn3O4 NPs at 150 degrees C is indirectly due to the higher oxygen vacancy occupancies, which supported the crystallinity decrease. Our findings provide a new perspective on manganese oxide formation in hydrothermal systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The intricate role of temperature in the structure-property relationship of manganese oxide nanoparticles (Mn3O4 NPs) remains an open question. In this study, we successfully synthesized Mn3O4 NPs using the hydrothermal method with two differing temperatures, namely, 90 and 150 degrees C. Interestingly, a smaller average particle size is found when Mn3O4 NPs are synthesized at 150 degrees C compared to 90 degrees C, corresponding to 46.54 and 63.37 nm, respectively. This was confirmed by the time variation of temperature setting of 150 degrees C where the size evolution was insignificant, indicating a competing effect of nucleation and growth particles. Under varying NaOH concentrations (2-6 M) at 150 degrees C, a reduction in the particle size is found at the highest NaOH concentration (6 M). The particle grows slightly, indicating that the growth state is dominant compared to the nucleation state at low concentrations of NaOH. This finding implies that the high nucleation rate originates from the excessive monomer supply in the high-temperature reaction. In terms of crystallinity order, the structural arrangement of Mn3O4 NPs (150 degrees C) is largely decreased; this is likely due to a facile redox shift to the higher oxidation state of manganese. In addition, the higher ratio of adsorbed oxygen and lattice oxygen in Mn3O4 NPs at 150 degrees C is indirectly due to the higher oxygen vacancy occupancies, which supported the crystallinity decrease. Our findings provide a new perspective on manganese oxide formation in hydrothermal systems. |
Ye, Rong; Sun, Xiangcheng; Mao, Xianwen; Alfonso, Felix S; Baral, Susil; Liu, Chunming; Coates, Geoffrey W; Chen, Peng Optical sequencing of single synthetic polymers Journal Article NATURE CHEMISTRY, 2023, ISSN: 1755-4330. @article{ISI:001156099000001, title = {Optical sequencing of single synthetic polymers}, author = {Rong Ye and Xiangcheng Sun and Xianwen Mao and Felix S Alfonso and Susil Baral and Chunming Liu and Geoffrey W Coates and Peng Chen}, doi = {10.1038/s41557-023-01363-2}, times_cited = {0}, issn = {1755-4330}, year = {2023}, date = {2023-11-09}, journal = {NATURE CHEMISTRY}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are generally unknown and inaccessible to traditional measurements. Here we report real-time optical sequencing of single synthetic copolymer chains under living polymerization conditions. We achieve this by carrying out multi-colour imaging of polymer growth by single catalysts at single-monomer resolution using CREATS (coupled reaction approach toward super-resolution imaging). CREATS makes a reaction effectively fluorogenic, enabling single-molecule localization microscopy of chemical reactions at higher reactant concentrations. Our data demonstrate that the chain propagation kinetics of surface-grafted polymerization contains temporal fluctuations with a defined memory time (which can be attributed to neighbouring monomer interactions) and chain-length dependence (due to surface electrostatic effects). Furthermore, the microscopic sequences of individual copolymers reveal their tendency to form block copolymers, and, more importantly, quantify the size distribution of individual blocks for comparison with theoretically random copolymers. Such sequencing capability paves the way for single-chain-level structure-function correlation studies of synthetic polymers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are generally unknown and inaccessible to traditional measurements. Here we report real-time optical sequencing of single synthetic copolymer chains under living polymerization conditions. We achieve this by carrying out multi-colour imaging of polymer growth by single catalysts at single-monomer resolution using CREATS (coupled reaction approach toward super-resolution imaging). CREATS makes a reaction effectively fluorogenic, enabling single-molecule localization microscopy of chemical reactions at higher reactant concentrations. Our data demonstrate that the chain propagation kinetics of surface-grafted polymerization contains temporal fluctuations with a defined memory time (which can be attributed to neighbouring monomer interactions) and chain-length dependence (due to surface electrostatic effects). Furthermore, the microscopic sequences of individual copolymers reveal their tendency to form block copolymers, and, more importantly, quantify the size distribution of individual blocks for comparison with theoretically random copolymers. Such sequencing capability paves the way for single-chain-level structure-function correlation studies of synthetic polymers. |
Xie, Jin; Zhou, Wenqiao; Mao, Xianwen; Liu, Chunming Characterization of single synthetic polymers via magnetic tweezers Journal Article JOURNAL OF POLYMER SCIENCE, 62 (7), pp. 1260-1276, 2023, ISSN: 2642-4150. @article{ISI:001094757800001, title = {Characterization of single synthetic polymers via magnetic tweezers}, author = {Jin Xie and Wenqiao Zhou and Xianwen Mao and Chunming Liu}, doi = {10.1002/pol.20230688}, times_cited = {0}, issn = {2642-4150}, year = {2023}, date = {2023-11-06}, journal = {JOURNAL OF POLYMER SCIENCE}, volume = {62}, number = {7}, pages = {1260-1276}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {Due to the ability to perform the parallel measurement of multiple single chains and exert precise control over stretching force in the sub-nanonewton regime, magnetic tweezers (MT) are a suitable tool to study the individual chain conformations and inherent behaviors of polymers. Herein, we examined the applications of MT in studying single synthetic polymers, distinct from previous reviews focusing on biological polymers such as DNAs. We first presented an overview of the technical aspects of MT, including the imaging setup, the algorithm of three-dimensional single particle tracking, the configuration of magnets, the calibration and control of magnetic forces, the assembly of flow cells, and the polymer tethering methods. Then, we discussed selected examples highlighting the utilization of MT in studying the chain conformation, mechanical properties, ion and ligands effect, regime transition mechanism, and polymerization dynamics of single synthetic polymers. We envision that MT can serve as a powerful toolbox for delving into the structure-property correlations at the single chain level, which provides quantitative validations for building the theoretical models of synthetic polymers. In the end, we contemplated potential avenues and opportunities for future research in this domain.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Due to the ability to perform the parallel measurement of multiple single chains and exert precise control over stretching force in the sub-nanonewton regime, magnetic tweezers (MT) are a suitable tool to study the individual chain conformations and inherent behaviors of polymers. Herein, we examined the applications of MT in studying single synthetic polymers, distinct from previous reviews focusing on biological polymers such as DNAs. We first presented an overview of the technical aspects of MT, including the imaging setup, the algorithm of three-dimensional single particle tracking, the configuration of magnets, the calibration and control of magnetic forces, the assembly of flow cells, and the polymer tethering methods. Then, we discussed selected examples highlighting the utilization of MT in studying the chain conformation, mechanical properties, ion and ligands effect, regime transition mechanism, and polymerization dynamics of single synthetic polymers. We envision that MT can serve as a powerful toolbox for delving into the structure-property correlations at the single chain level, which provides quantitative validations for building the theoretical models of synthetic polymers. In the end, we contemplated potential avenues and opportunities for future research in this domain. |
Lin, Fanrong; Cao, Zhonghan; Xiao, Feiping; Liu, Jiawei; Qiao, Jiabin; Xue, Minmin; Hu, Zhili; Liu, Ying; Lu, Huan; Zhang, Zhuhua; Martin, Jens; Tong, Qingjun; Guo, Wanlin; Liu, Yanpeng Graphene binding on black phosphorus enables high on/off ratios and mobility Journal Article NATIONAL SCIENCE REVIEW, 11 (2), 2023, ISSN: 2095-5138. @article{ISI:001121789900001, title = {Graphene binding on black phosphorus enables high on/off ratios and mobility}, author = {Fanrong Lin and Zhonghan Cao and Feiping Xiao and Jiawei Liu and Jiabin Qiao and Minmin Xue and Zhili Hu and Ying Liu and Huan Lu and Zhuhua Zhang and Jens Martin and Qingjun Tong and Wanlin Guo and Yanpeng Liu}, doi = {10.1093/nsr/nwad279}, times_cited = {0}, issn = {2095-5138}, year = {2023}, date = {2023-11-03}, journal = {NATIONAL SCIENCE REVIEW}, volume = {11}, number = {2}, publisher = {OXFORD UNIV PRESS}, address = {GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND}, abstract = {Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >103 as well as a mobility of similar to 8000 cm(2) V-1 s(-1) at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >103 as well as a mobility of similar to 8000 cm(2) V-1 s(-1) at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems. |
Whitcher, T J; Fauzi, A D; Diao, C; Chi, X; Syahroni, A; Asmara, T C; Breese, M B H; Neto, Castro A H; Wee, A T S; Majidi, M A; Rusydi, A Reply to: Reassessing the existence of soft X-ray correlated plasmons Journal Article NATURE COMMUNICATIONS, 14 (1), 2023. @article{ISI:001089230100018, title = {Reply to: Reassessing the existence of soft X-ray correlated plasmons}, author = {T J Whitcher and A D Fauzi and C Diao and X Chi and A Syahroni and T C Asmara and M B H Breese and Castro A H Neto and A T S Wee and M A Majidi and A Rusydi}, doi = {10.1038/s41467-023-40652-9}, times_cited = {0}, year = {2023}, date = {2023-10-24}, journal = {NATURE COMMUNICATIONS}, volume = {14}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Jiang, Zhuoling; Yam, Kah-Meng; Ang, Yee Sin; Guo, Na; Zhang, Yongjie; Wang, Hao; Zhang, Chun Symmetry-driven half-integer conductance quantization in Cobalt-fulvalene sandwich nanowire Journal Article NPJ COMPUTATIONAL MATERIALS, 9 (1), 2023. @article{ISI:001095847100002, title = {Symmetry-driven half-integer conductance quantization in Cobalt-fulvalene sandwich nanowire}, author = {Zhuoling Jiang and Kah-Meng Yam and Yee Sin Ang and Na Guo and Yongjie Zhang and Hao Wang and Chun Zhang}, doi = {10.1038/s41524-023-01151-z}, times_cited = {0}, year = {2023}, date = {2023-10-21}, journal = {NPJ COMPUTATIONAL MATERIALS}, volume = {9}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Precise manipulation and monitoring spin transport in one-dimensional (1D) systems is a long-sought goal in the field of nano-spintronics. Based on first-principles calculations, we report the observation of half-integer conductance quantization in the Cobalt-fulvalene sandwich nanowire. Compared with a pure monatomic Cobalt wire, the introduction of fulvalene molecules leads to three important features: Firstly, the strong coupling between the fulvalene and the Cobalt prevents the contamination of the ambient air, ensuring both chemical and physical stabilities; Secondly, the fulvalene symmetry-selectively filters out most of the d-type orbitals of the Cobalt while leaving a single d-type orbital to form an open spin channel around the Fermi level, which offers a mechanism to achieve the observed half-integer conductance; Thirdly, it maintains a superexchange coupling between adjacent Co atoms to achieve a high Curie temperature. Spin transport calculations show that this half-metallic nanowire can serve as a perfect spin filter or a spin valve device, thus revealing the potential of Cobalt-fulvalene sandwich nanowire as a promising building block of high-performance spintronics technology.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Precise manipulation and monitoring spin transport in one-dimensional (1D) systems is a long-sought goal in the field of nano-spintronics. Based on first-principles calculations, we report the observation of half-integer conductance quantization in the Cobalt-fulvalene sandwich nanowire. Compared with a pure monatomic Cobalt wire, the introduction of fulvalene molecules leads to three important features: Firstly, the strong coupling between the fulvalene and the Cobalt prevents the contamination of the ambient air, ensuring both chemical and physical stabilities; Secondly, the fulvalene symmetry-selectively filters out most of the d-type orbitals of the Cobalt while leaving a single d-type orbital to form an open spin channel around the Fermi level, which offers a mechanism to achieve the observed half-integer conductance; Thirdly, it maintains a superexchange coupling between adjacent Co atoms to achieve a high Curie temperature. Spin transport calculations show that this half-metallic nanowire can serve as a perfect spin filter or a spin valve device, thus revealing the potential of Cobalt-fulvalene sandwich nanowire as a promising building block of high-performance spintronics technology. |
Zhang, Yi; Zhang, Yongjie; Gu, Kaixuan; Zhang, Linfeng; Zhu, Yuanmin; Liu, Dianzi; Deng, Hui A General and Ultrafast Polishing Method with Truly Atomic Roughness Journal Article JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 14 (42), pp. 9441-9447, 2023, ISSN: 1948-7185. @article{ISI:001090563200001, title = {A General and Ultrafast Polishing Method with Truly Atomic Roughness}, author = {Yi Zhang and Yongjie Zhang and Kaixuan Gu and Linfeng Zhang and Yuanmin Zhu and Dianzi Liu and Hui Deng}, doi = {10.1021/acs.jpclett.3c02322}, times_cited = {0}, issn = {1948-7185}, year = {2023}, date = {2023-10-12}, journal = {JOURNAL OF PHYSICAL CHEMISTRY LETTERS}, volume = {14}, number = {42}, pages = {9441-9447}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The advancement of science and technology is always accompanied by better manufacturing precision. Ideally, the highest precision for manufacturing a surface is truly atomic flatness, which implies that all topmost surface atoms are in a single layer of the crystal face. However, almost no methods can achieve this surface with high efficiency at present. Herein, we present a method to fabricate a large-scale truly atomically flat surface with ultrafast speed. Through the selective etching of surface atoms, our method can achieve an atomically flat surface with 0.05 nm Sa roughness. It is notable that the polishing efficiency of our method is more than 1000 times higher than that of conventional methods. We have demonstrated its generality on various single-crystal materials and obtained atomic roughness and an ultrahigh polishing rate. This method has the potential to promote the mass-production of atomic-scale smooth surfaces, the application of third-generation semiconductor materials, and the innovation of advanced technologies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The advancement of science and technology is always accompanied by better manufacturing precision. Ideally, the highest precision for manufacturing a surface is truly atomic flatness, which implies that all topmost surface atoms are in a single layer of the crystal face. However, almost no methods can achieve this surface with high efficiency at present. Herein, we present a method to fabricate a large-scale truly atomically flat surface with ultrafast speed. Through the selective etching of surface atoms, our method can achieve an atomically flat surface with 0.05 nm Sa roughness. It is notable that the polishing efficiency of our method is more than 1000 times higher than that of conventional methods. We have demonstrated its generality on various single-crystal materials and obtained atomic roughness and an ultrahigh polishing rate. This method has the potential to promote the mass-production of atomic-scale smooth surfaces, the application of third-generation semiconductor materials, and the innovation of advanced technologies. |
Kazzi, Salim El; Lum, Ya Woon; Erofeev, Ivan; Vajandar, Saumitra; Pasko, Sergej; Krotkus, Simonas; Conran, Ben; Whear, Oliver; Osipowicz, Thomas; Mirsaidov, Utkur Assessing Ultrathin Wafer-Scale WS2 as a Diffusion Barrier for Cu Interconnects Journal Article ACS APPLIED ELECTRONIC MATERIALS, 5 (9), pp. 5074-5081, 2023. @article{ISI:001062611700001, title = {Assessing Ultrathin Wafer-Scale WS_{2} as a Diffusion Barrier for Cu Interconnects}, author = {Salim El Kazzi and Ya Woon Lum and Ivan Erofeev and Saumitra Vajandar and Sergej Pasko and Simonas Krotkus and Ben Conran and Oliver Whear and Thomas Osipowicz and Utkur Mirsaidov}, doi = {10.1021/acsaelm.3c00809}, times_cited = {0}, year = {2023}, date = {2023-09-05}, journal = {ACS APPLIED ELECTRONIC MATERIALS}, volume = {5}, number = {9}, pages = {5074-5081}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {To maintain the scaling trends in the complementary metal oxide semiconductor (CMOS) technology, the thickness of barrier/liner systems used in back-end-of-line (BEOL) fabrication of metal interconnects needs to be sub-2 nm. However, reducing the thickness of the traditional barrier and liner systems necessary for the dimensional scaling of future interconnects is extremely challenging. Hence, ultrathin two-dimensional (2D) transition-metal dichalcogenide (TMD) films can be an alternative to current barrier/liner systems. However, the processes used to grow these films are generally not BEOL-compatible. Here, using the plasma-free metal-organic chemical vapor deposition (MOCVD) process, we grow BEOL-compatible tungsten disulfide (WS2) film, which has a clear advantage over current diffusion barrier/liner systems used in Cu-interconnects. Our results show that these WS2 films not only block Cu diffusion but also reduce the effective resistance of the Cu film by suppressing the grain boundary and interface scattering of electrons.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To maintain the scaling trends in the complementary metal oxide semiconductor (CMOS) technology, the thickness of barrier/liner systems used in back-end-of-line (BEOL) fabrication of metal interconnects needs to be sub-2 nm. However, reducing the thickness of the traditional barrier and liner systems necessary for the dimensional scaling of future interconnects is extremely challenging. Hence, ultrathin two-dimensional (2D) transition-metal dichalcogenide (TMD) films can be an alternative to current barrier/liner systems. However, the processes used to grow these films are generally not BEOL-compatible. Here, using the plasma-free metal-organic chemical vapor deposition (MOCVD) process, we grow BEOL-compatible tungsten disulfide (WS2) film, which has a clear advantage over current diffusion barrier/liner systems used in Cu-interconnects. Our results show that these WS2 films not only block Cu diffusion but also reduce the effective resistance of the Cu film by suppressing the grain boundary and interface scattering of electrons. |
Shen, Kai; Mathur, Anmol; Liu, Yayuan; Mao, Xianwen Electrochemically responsive materials for energy-efficient water treatment and carbon capture Journal Article APPLIED PHYSICS REVIEWS, 10 (3), 2023, ISSN: 1931-9401. @article{ISI:001037216000001, title = {Electrochemically responsive materials for energy-efficient water treatment and carbon capture}, author = {Kai Shen and Anmol Mathur and Yayuan Liu and Xianwen Mao}, doi = {10.1063/5.0147071}, times_cited = {0}, issn = {1931-9401}, year = {2023}, date = {2023-09-01}, journal = {APPLIED PHYSICS REVIEWS}, volume = {10}, number = {3}, publisher = {AIP Publishing}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {Electrochemically responsive materials (ERMs) that respond to external electrical stimuli offer advanced control over physio-chemical processes with a high degree of tunability and flexibility. Recently, the use of ERMs in environmental remediation processes has increased to address the grand sustainability challenges associated with water scarcity and climate change. Here, we provide a timely review on the applications of ERMs to electrochemically mediated water treatment (EMWT) and electrochemically mediated carbon capture (EMCC). We first examine the working principles of ERMs-based systems for water treatment and carbon capture, followed by a detailed summary of key figures of merit that quantify the overall performance. Second, we present an in-depth discussion of the multiscale design principles of EMWT and EMCC systems, ranging from materials-level engineering to electrode-level considerations to device configuration optimization. Next, we discuss the development and application of in situ and operando characterization methods, with a particular emphasis on imaging tools, which uncover ubiquitous static and dynamic heterogeneities in ERMs and critically inform rational materials design. Finally, we point out future opportunities and challenges in the emerging field of electrochemically mediated environmental remediation, including developing new tools to monitor complex multiphase transport and reactions, repurposing existing energy nanomaterials for environmental technologies, and scaling and combining EMWT and EMCC systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electrochemically responsive materials (ERMs) that respond to external electrical stimuli offer advanced control over physio-chemical processes with a high degree of tunability and flexibility. Recently, the use of ERMs in environmental remediation processes has increased to address the grand sustainability challenges associated with water scarcity and climate change. Here, we provide a timely review on the applications of ERMs to electrochemically mediated water treatment (EMWT) and electrochemically mediated carbon capture (EMCC). We first examine the working principles of ERMs-based systems for water treatment and carbon capture, followed by a detailed summary of key figures of merit that quantify the overall performance. Second, we present an in-depth discussion of the multiscale design principles of EMWT and EMCC systems, ranging from materials-level engineering to electrode-level considerations to device configuration optimization. Next, we discuss the development and application of in situ and operando characterization methods, with a particular emphasis on imaging tools, which uncover ubiquitous static and dynamic heterogeneities in ERMs and critically inform rational materials design. Finally, we point out future opportunities and challenges in the emerging field of electrochemically mediated environmental remediation, including developing new tools to monitor complex multiphase transport and reactions, repurposing existing energy nanomaterials for environmental technologies, and scaling and combining EMWT and EMCC systems. |
Tang, Chi Sin; Zeng, Shengwei; Wu, Jing; Chen, Shunfeng; Naradipa, Muhammad A; Song, Dongsheng; Milosevic, M V; Yang, Ping; Diao, Caozheng; Zhou, Jun; Pennycook, Stephen J; Breese, Mark B H; Cai, Chuanbing; Venkatesan, Thirumalai; Ariando, Ariando; Yang, Ming; Wee, Andrew T S; Yin, Xinmao Detection of two-dimensional small polarons at oxide interfaces by optical spectroscopy Journal Article APPLIED PHYSICS REVIEWS, 10 (3), 2023, ISSN: 1931-9401. @article{ISI:001038283300001, title = {Detection of two-dimensional small polarons at oxide interfaces by optical spectroscopy}, author = {Chi Sin Tang and Shengwei Zeng and Jing Wu and Shunfeng Chen and Muhammad A Naradipa and Dongsheng Song and M V Milosevic and Ping Yang and Caozheng Diao and Jun Zhou and Stephen J Pennycook and Mark B H Breese and Chuanbing Cai and Thirumalai Venkatesan and Ariando Ariando and Ming Yang and Andrew T S Wee and Xinmao Yin}, doi = {10.1063/5.0141814}, times_cited = {0}, issn = {1931-9401}, year = {2023}, date = {2023-09-01}, journal = {APPLIED PHYSICS REVIEWS}, volume = {10}, number = {3}, publisher = {AIP Publishing}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {Two-dimensional (2D) perovskite oxide interfaces are ideal systems to uncover diverse emergent properties, such as the arising polaronic properties from short-range charge-lattice interactions. Thus, a technique to detect this quasiparticle phenomenon at the buried interface is highly coveted. Here, we report the observation of 2D small-polarons at the LaAlO3/SrTiO3 conducting interface using high-resolution spectroscopic ellipsometry. First-principles investigations show that interfacial electron-lattice coupling mediated by the longitudinal phonon mode facilitates the formation of these polarons. This study resolves the long-standing question by attributing the formation of interfacial 2D small polarons to the significant mismatch between experimentally measured interfacial carrier density and theoretical values. Our study sheds light on the complexity of broken periodic lattice-induced quasi-particle effects and its relationship with exotic phenomena at complex oxide interfaces. Meanwhile, this work establishes spectroscopic ellipsometry as a useful technique to detect and locate optical evidence of polaronic states and other emerging quantum properties at the buried interface.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional (2D) perovskite oxide interfaces are ideal systems to uncover diverse emergent properties, such as the arising polaronic properties from short-range charge-lattice interactions. Thus, a technique to detect this quasiparticle phenomenon at the buried interface is highly coveted. Here, we report the observation of 2D small-polarons at the LaAlO3/SrTiO3 conducting interface using high-resolution spectroscopic ellipsometry. First-principles investigations show that interfacial electron-lattice coupling mediated by the longitudinal phonon mode facilitates the formation of these polarons. This study resolves the long-standing question by attributing the formation of interfacial 2D small polarons to the significant mismatch between experimentally measured interfacial carrier density and theoretical values. Our study sheds light on the complexity of broken periodic lattice-induced quasi-particle effects and its relationship with exotic phenomena at complex oxide interfaces. Meanwhile, this work establishes spectroscopic ellipsometry as a useful technique to detect and locate optical evidence of polaronic states and other emerging quantum properties at the buried interface. |
Tang, Chi Sin; Zeng, Shengwei; Wu, Jing; Chen, Shunfeng; Naradipa, Muhammad A; Song, Dongsheng; Milosevic, M V; Yang, Ping; Diao, Caozheng; Zhou, Jun; Pennycook, Stephen J; Breese, Mark B H; Cai, Chuanbing; Venkatesan, Thirumalai; Ariando, Ariando; Yang, Ming; Wee, Andrew T S; Yin, Xinmao "Detection of two-dimensional small polarons at oxide interfaces by optical spectroscopy" (vol 10, 031406 2023) Journal Article APPLIED PHYSICS REVIEWS, 10 (3), 2023, ISSN: 1931-9401. @article{ISI:001062976900001, title = {"Detection of two-dimensional small polarons at oxide interfaces by optical spectroscopy" (vol 10, 031406 2023)}, author = {Chi Sin Tang and Shengwei Zeng and Jing Wu and Shunfeng Chen and Muhammad A Naradipa and Dongsheng Song and M V Milosevic and Ping Yang and Caozheng Diao and Jun Zhou and Stephen J Pennycook and Mark B H Breese and Chuanbing Cai and Thirumalai Venkatesan and Ariando Ariando and Ming Yang and Andrew T S Wee and Xinmao Yin}, doi = {10.1063/5.0173910}, times_cited = {0}, issn = {1931-9401}, year = {2023}, date = {2023-09-01}, journal = {APPLIED PHYSICS REVIEWS}, volume = {10}, number = {3}, publisher = {AIP Publishing}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Fang, Hanyan; Mahalingam, Harshitra; Li, Xinzhe; Han, Xu; Qiu, Zhizhan; Han, Yixuan; Noori, Keian; Dulal, Dikshant; Chen, Hongfei; Lyu, Pin; Yang, Tianhao; Li, Jing; Su, Chenliang; Chen, Wei; Cai, Yongqing; Neto, Castro A H; Novoselov, Kostya S; Rodin, Aleksandr; Lu, Jiong Atomically precise vacancy-assembled quantum antidots Journal Article NATURE NANOTECHNOLOGY, 18 (12), 2023, ISSN: 1748-3387. @article{ISI:001062548200002, title = {Atomically precise vacancy-assembled quantum antidots}, author = {Hanyan Fang and Harshitra Mahalingam and Xinzhe Li and Xu Han and Zhizhan Qiu and Yixuan Han and Keian Noori and Dikshant Dulal and Hongfei Chen and Pin Lyu and Tianhao Yang and Jing Li and Chenliang Su and Wei Chen and Yongqing Cai and Castro A H Neto and Kostya S Novoselov and Aleksandr Rodin and Jiong Lu}, doi = {10.1038/s41565-023-01495-z}, times_cited = {0}, issn = {1748-3387}, year = {2023}, date = {2023-08-31}, journal = {NATURE NANOTECHNOLOGY}, volume = {18}, number = {12}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Patterning antidots, which are regions of potential hills that repel electrons, into well-defined antidot lattices creates fascinating artificial periodic structures, leading to anomalous transport properties and exotic quantum phenomena in two-dimensional systems. Although nanolithography has brought conventional antidots from the semiclassical regime to the quantum regime, achieving precise control over the size of each antidot and its spatial period at the atomic scale has remained challenging. However, attaining such control opens the door to a new paradigm, enabling the creation of quantum antidots with discrete quantum hole states, which, in turn, offer a fertile platform to explore novel quantum phenomena and hot electron dynamics in previously inaccessible regimes. Here we report an atomically precise bottom-up fabrication of a series of atomic-scale quantum antidots through a thermal-induced assembly of a chalcogenide single vacancy in PtTe2. Such quantum antidots consist of highly ordered single-vacancy lattices, spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of single vacancies in quantum antidots strengthens the cumulative repulsive potential and consequently enhances the collective interference of multiple-pocket scattered quasiparticles inside quantum antidots, creating multilevel quantum hole states with a tunable gap from the telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of quantum antidots are geometry protected and thus survive on oxygen substitutional doping. Therefore, single-vacancy-assembled quantum antidots exhibit unprecedented robustness and property tunability, positioning them as highly promising candidates for advancing quantum information and photocatalysis technologies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Patterning antidots, which are regions of potential hills that repel electrons, into well-defined antidot lattices creates fascinating artificial periodic structures, leading to anomalous transport properties and exotic quantum phenomena in two-dimensional systems. Although nanolithography has brought conventional antidots from the semiclassical regime to the quantum regime, achieving precise control over the size of each antidot and its spatial period at the atomic scale has remained challenging. However, attaining such control opens the door to a new paradigm, enabling the creation of quantum antidots with discrete quantum hole states, which, in turn, offer a fertile platform to explore novel quantum phenomena and hot electron dynamics in previously inaccessible regimes. Here we report an atomically precise bottom-up fabrication of a series of atomic-scale quantum antidots through a thermal-induced assembly of a chalcogenide single vacancy in PtTe2. Such quantum antidots consist of highly ordered single-vacancy lattices, spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of single vacancies in quantum antidots strengthens the cumulative repulsive potential and consequently enhances the collective interference of multiple-pocket scattered quasiparticles inside quantum antidots, creating multilevel quantum hole states with a tunable gap from the telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of quantum antidots are geometry protected and thus survive on oxygen substitutional doping. Therefore, single-vacancy-assembled quantum antidots exhibit unprecedented robustness and property tunability, positioning them as highly promising candidates for advancing quantum information and photocatalysis technologies. |
Li, Hongkun; Pandey, Tribhuwan; Jiang, Yi; Gu, Xiaokun; Lindsay, Lucas; Koh, Yee Kan Origins of heat transport anisotropy in MoTe2 and other bulk van der Waals materials Journal Article MATERIALS TODAY PHYSICS, 37 , 2023, ISSN: 2542-5293. @article{ISI:001093005700001, title = {Origins of heat transport anisotropy in MoTe_{2} and other bulk van der Waals materials}, author = {Hongkun Li and Tribhuwan Pandey and Yi Jiang and Xiaokun Gu and Lucas Lindsay and Yee Kan Koh}, doi = {10.1016/j.mtphys.2023.101196}, times_cited = {0}, issn = {2542-5293}, year = {2023}, date = {2023-08-29}, journal = {MATERIALS TODAY PHYSICS}, volume = {37}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {Knowledge of how heat flows anisotropically in van der Waals (vdW) materials is crucial for thermal management of emerging 2D materials devices and design of novel anisotropic thermoelectric materials. Despite the importance, anisotropic heat transport in vdW materials is yet to be systematically studied and is often presumably attributed to anisotropic speeds of sound in vdW materials due to soft interlayer bonding relative to covalent in-plane networks of atoms. In this work, we investigate the origins of the anisotropic heat transport in vdW materials, through time-domain thermoreflectance (TDTR) measurements and first-principles calculations of anisotropic thermal conductivity of three different phases of MoTe2. MoTe2 is ideal for the study due to its weak anisotropy in the speeds of sound. We find that even when the speeds of sound are roughly isotropic, the measured thermal conductivity of MoTe2 along the c-axis is 5-8 times lower than that along the in-plane axes. We derive meaningful characteristic heat capacity, phonon group velocity, and relaxation times from our first principles calculations for selected vdW materials (MoTe2, BP, h-BN, and MoS2), to assess the contributions of these factors to the anisotropic heat transport. Interestingly, we find that the main contributor to the heat transport anisotropy in vdW materials is anisotropy in heat capacity of the dominant heat-carrying phonon modes in different directions, which originates from anisotropic optical phonon dispersion and disparity in the frequency of heat-carrying phonons in different directions. The discrepancy in frequency of the heat-carrying phonons also leads to similar to 2 times larger average relaxation times in the cross-plane direction, and partially explains the apparent dependence of the anisotropic heat transport on the anisotropic speeds of sound. This work provides insight into understanding of the anisotropic heat transport in vdW materials.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Knowledge of how heat flows anisotropically in van der Waals (vdW) materials is crucial for thermal management of emerging 2D materials devices and design of novel anisotropic thermoelectric materials. Despite the importance, anisotropic heat transport in vdW materials is yet to be systematically studied and is often presumably attributed to anisotropic speeds of sound in vdW materials due to soft interlayer bonding relative to covalent in-plane networks of atoms. In this work, we investigate the origins of the anisotropic heat transport in vdW materials, through time-domain thermoreflectance (TDTR) measurements and first-principles calculations of anisotropic thermal conductivity of three different phases of MoTe2. MoTe2 is ideal for the study due to its weak anisotropy in the speeds of sound. We find that even when the speeds of sound are roughly isotropic, the measured thermal conductivity of MoTe2 along the c-axis is 5-8 times lower than that along the in-plane axes. We derive meaningful characteristic heat capacity, phonon group velocity, and relaxation times from our first principles calculations for selected vdW materials (MoTe2, BP, h-BN, and MoS2), to assess the contributions of these factors to the anisotropic heat transport. Interestingly, we find that the main contributor to the heat transport anisotropy in vdW materials is anisotropy in heat capacity of the dominant heat-carrying phonon modes in different directions, which originates from anisotropic optical phonon dispersion and disparity in the frequency of heat-carrying phonons in different directions. The discrepancy in frequency of the heat-carrying phonons also leads to similar to 2 times larger average relaxation times in the cross-plane direction, and partially explains the apparent dependence of the anisotropic heat transport on the anisotropic speeds of sound. This work provides insight into understanding of the anisotropic heat transport in vdW materials. |