Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Two-dimensional Materials I (joint session HL/CPP)
HL 17.5: Vortrag
Dienstag, 2. April 2019, 10:30–10:45, H36
Interlayer band-to-band tunneling in h-BN encapsulated MoS2-WSe2 heterojunction — •Phanish Chava1,2, Vivek Mootheri1, Himani Arora1,2, Kenji Wantanbe3, Takashi Taniguchi3, Manfred Helm1, and Artur Erbe1 — 1Helmholtz Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden, Germany — 2TU Dresden, 01062 Dresden, Germany — 3National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
Quantum mechanical band-to-band tunneling (BTBT) is a particular type of carrier injection mechanism which is responsible for the electronic transport in tunneling based devices like Esaki diode and Tunnel Field Effect Transistor (TFET). Atomically thin layers of transition metal dichalcogenides (TMDCs) are promising semiconducting materials for realizing such devices owing to their sharp interfaces. In this work, we demonstrate BTBT between the layers of molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) in a MoS2-WSe2 heterojunction which is encapsulated with hexagonal boron nitride (h-BN) on the top and bottom. Also, we employ few-layer graphene as the contact material to the heterojunction thereby forming a 2D-2D van der Waals contact. We find that the device works as a p-TFET for for negative top gate voltages and an n-MOSFET for positive top gate voltages. The device exhibits Negative Transconductance (NTC) in the positive gate voltage regime, a minimum sub-threshold swing of about 170 mV / dec at 125 K and an ON-OFF ratio of about 106.