Electron Transport across Vertical Silicon/MoS2/Graphene Heterostructures: Towards Efficient Emitter Diodes for Graphene Base Hot Electron Transistors

ACS Applied Materials & Interfaces, vol. 12, pp. 9656–9663

Abstract

Abstract Heterostructures comprising silicon, molybdenum disulfide (MoS2), and graphene are investigated with respect to the vertical current conduction mechanism. The measured current–voltage (I–V) characteristics exhibit temperature-dependent asymmetric current, indicating thermally activated charge carrier transport. The data are compared and fitted to a current transport model that confirms thermionic emission as the responsible transport mechanism across devices. Theoretical calculations in combination with the experimental data suggest that the heterojunction barrier from Si to MoS2 is linearly temperature-dependent for T = 200–300 K with a positive temperature coefficient. The temperature dependence may be attributed to a change in band gap difference between Si and MoS2, strain at the Si/MoS2 interface, or different electron effective masses in Si and MoS2, leading to a possible entropy change stemming from variation in density of states as electrons move from Si to MoS2. The low barrier formed between Si and MoS2 and the resultant thermionic emission demonstrated here make the present devices potential candidates as the emitter diode of graphene base hot electron transistors for future high-speed electronics.

Authors 7

1. Melkamu Belete Aachen Faculty of Electrical Engineering and Information Technology Chair of Electronic Devices

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University , , Otto-Blumenthal-Str. 2 , ,

   Faculty of Electrical Engineering and Information Technology, Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 2, 52074 Aachen, Germany

2. Olof Engström Aachen AMO GmbH

   AMO (Germany)

   Affiliation as printed

   AMO GmbH , Otto-Blumenthal-Str. 25 , ,

   AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany

3. Sam Vaziri

   Stanford University

   Affiliation as printed

   Stanford University , , , ,

   Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States

4. G. Lippert

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP─Leibniz-Institut für innovative Mikroelektronik , (Oder),

   IHP—Leibniz-Institut für innovative Mikroelektronik, 15236 Frankfurt (Oder), Germany

5. Mindaugas Lukosius

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP─Leibniz-Institut für innovative Mikroelektronik , (Oder),

   IHP—Leibniz-Institut für innovative Mikroelektronik, 15236 Frankfurt (Oder), Germany

6. Satender Kataria corresponding Aachen Faculty of Electrical Engineering and Information Technology Chair of Electronic Devices

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University , , Otto-Blumenthal-Str. 2 , ,

   Faculty of Electrical Engineering and Information Technology, Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 2, 52074 Aachen, Germany

7. Max C. Lemme corresponding Aachen AMO GmbH Faculty of Electrical Engineering and Information Technology Chair of Electronic Devices

   RWTH Aachen University · AMO (Germany)

   Affiliation as printed

   AMO GmbH , Otto-Blumenthal-Str. 25 , ,

   RWTH Aachen University , , Otto-Blumenthal-Str. 2 , ,

   AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany

   Faculty of Electrical Engineering and Information Technology, Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 2, 52074 Aachen, Germany