| AVS 61st International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+AS+HI+NS+SS-ThM |
| Session: | Nanostructures including 2D Heterostructures, Patterning of 2D Materials |
| Presenter: | Deep Jariwala, Northwestern University |
| Authors: | D. Jariwala, Northwestern University V.K. Sangwan, Northwestern University C.-C. Wu, Northwestern University P.L. Prabhumirashi, Northwestern University M.L. Geier, Northwestern University T.J. Marks, Northwestern University L.J. Lauhon, Northwestern University M.C. Hersam, Northwestern University |
| Correspondent: | Click to Email |
The isolation of graphene and the subsequent reports on its electronic properties have spurred tremendous interest in a variety of two dimensional (2D) materials for electronic device applications. Layered semiconducting transition metal dichalcogenides (TMDCs) of Mo and W have emerged as promising alternatives to graphene for optoelectronic applications due to their finite band gap in the visible portion of the electromagnetic spectrum.1 The atomically thin structure of these 2D materials coupled with van der Waals bonding between adjacent layers allows their stacking into atomically sharp heterostructures with defect-free interfaces, in contrast to epitaxially grown III-V semiconductor heterostructures where the material choices are constrained by lattice matching. Additionally, the few atom thickness of the individual layers enables doping modulation of the overlying layers in a heterostructure using a global back gate. While a large number of heterostructure devices employing graphene have been reported, it’s gapless band structure prevents the formation of a large potential barrier for charge separation and current rectification. Consequently, a p-n heterojunction diode derived from ultrathin materials is notably absent and significantly constrains the fabrication of complex electronic and optoelectronic circuits. Here we demonstrate a gate-tunable p-n heterojunction diode using semiconducting single-walled carbon nanotubes (s-SWCNTs) and single-layer molybdenum disulphide (SL-MoS2) as atomically thin p-type and n-type semiconductors, respectively. The vertical stacking of these two direct band gap semiconductors forms a heterojunction with electrical characteristics that can be tuned with an applied gate bias over a wide range of charge transport behavior, ranging from insulating to rectifying with forward-to-reverse bias current ratios exceeding 104. In addition, the gate-dependent characteristics of this diode exhibit a unique 'anti-ambipolar' behavior with two off-states at either extremes of the gate voltage range and a maximum on-state current between them. This heterojunction diode also responds to optical irradiation with photoresponse time < 15 μs.2 We anticipate that the novel properties and characteristics of this p-n heterojunction can be widely generalized to other atomically thin materials systems.
REFERENCES:
1. Jariwala, D. et al. Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides. ACS Nano 2014 , 8, 1102–1120.
2. Jariwala, D. et al. Gate-Tunable Carbon Nanotube–MoS2 Heterojunction p-n Diode. Proc. Natl. Acad. Sci. U.S.A. 2013 , 110, 18076–18080.