The activities of PIs in the Graphene Research Group (GRG) cover:
- Van der Waals heterostructures
- Graphene Research
The graphene group continues to focus on graphene and 2D materials based van der Waals heterostructures. Increasingly, black phosphorus (BP), a 2D material first discovered at CA2DM in 2014, is starting to rival graphene as an equally promising material system for optoelectronics, electronics and even spintronics. The graphene group has also made progress in removing bottle necks in graphene synthesis, transfer and doping, which finally allows a more wide spread use of graphene and related materials for novel device application. These advances have allowed enhanced collaborations between PIs across faculties and enables more fruitful collaborations with Industry.
a) Van der Waals heterostructures
The graphene group has played a pioneering role in setting up a transfer system under inert gas conditions. Over the last year, a second custom-made transfer system has been now adapted to the needs at CA2DM such that a fully motorized transfer can take place within the inert gas environment of a glove box set-up. In a further joint developed with Graphene Industries, Inc., the latter is attached both to a second glove-box set-up with in situ-diagnostics tools (such as an AFM), UHV deposition chamber, an ALD chamber and an annealing chamber. Such a semi-automatic inline set-up will further increase both the throughput of device fab and the productive of the Centre. This contributes strongly to the mission of the Centre to bring together groups with different expertise. The aim is to further increase the potential impact of their ongoing through such collaborations and will allow much cleaner interfaces necessary for potentially ground-breaking discoveries. These stringent requirements also sharply cut the number of research groups who can compete in this field outside Singapore. The Centre is known for developing interdisciplinary strategies for tailoring and exploiting the physics properties of 2D materials. Among these, the following two publications on BP are worth highlighting:
1) Enhanced Photoresponse from Phosphorene–Phosphorene-Suboxide Junction Fashioned by Focused Laser Micromachining; Junpeng Lu , Alexandra Carvalho , Jing Wu , Hongwei Liu , Eng Soon Tok , Antonio H. Castro Neto , Barbaros Özyilmaz , * and Chorng Haur Sow *. Advanced Material (2016) 10411. Also featured on the cover.
2) “Gate-tunable Black Phosphorus Spin Valve with Nanosecond Spin lifetimes” by Ahmet Avsar, Jun Y. Tan, Marcin Kurpas, Martin Gmitra, Kenji Watanabe, Takashi Taniguchi, Jaroslav Fabian and Barbaros Özyilmaz , Nature Physics (in press).
A second area of intense efforts is the gate tunable spin based emerging phenomena in 2D materials. As a first step, we recently demonstrate that these effects are present in TMDCS or can be engineered via Au intercalation of 2D van der Waals heterostructures:
Quantum Transport and Observation of Dyakonov-Perel Spin-Orbit Scattering in Monolayer MoS 2
H Schmidt, I Yudhistira, L Chu, AHC Neto, B Özyilmaz, S Adam, G Eda
Physical review letters 116 (4), 046803
b) Graphene Research
Graphene has attracted a lot of interest from a wide range of industries. Graphene’s high mechanical strength & flexibility, optical transparency and exceptional heat & charge transport properties make it appealing for a wide range of novel device concepts. These range from flexible smart phones, roll-able AM-OLED, anti-bacterial coatings, water filtration membranes, photovoltaics, energy storage, etc. While proof-of-concepts, for most of these ideas, has already been realized at the lab scale, many challenges still lie ahead in terms of large scale synthesis, transfer and incorporation in existing industrial production processes.
More recently, With some of the roadblocks in graphene production being addressed, we are now in better positioned to pursue research collaboration which utilize 2D materials for addressing real world problems. While the actual industry collaborations are being pursued within OII, the graphene research group supports and accelerates these activities by aligning in some areas of basic research with applied research needs, e.g. to address shortcomings or opportunities in complementary areas highlighted to OII through company feedbacks.