Multifunctional anti-ambipolar p-n junction based on MoTe2/MoS2 heterostructure

Abstract

The discovery of atomically thin two-dimensional materials enables building numerous van der Waals heterostructures with original and promising properties for potential electronic and optoelectronic applications. Among them, the antiambipolar characteristic is one of the most appealing ones, which refers to the inverse “V” shape of the transfer curve of the heterojunction. As a result, it is expected to implement various important logic functions, such as double-frequency and multivalue. In this work, we modulated an ambipolar MoTe2/MoS2 heterojunction to show prominent antiambipolar behavior by simply annealing the device at elevated temperature. The on-off ratio and on-state current of the antiambipolar characteristic can be tuned as large as 106 and approximately microamperes, respectively, by optimizing the annealing temperature. Furthermore, we preliminarily demonstrated a self-powered photodetector and a ternary inverter based on this device. The photodetector showed a short-current circuit and an open-circuit voltage of 0.4 μA and 7.5 mV, respectively, at incident light intensity of 2.54 mW/cm2, and gate tunable photocurrent ranging from 0 to 380 pA under zero source-drain bias. The ternary inverter can output three distinct values varying on the order of subvolt as the input voltage (gate bias) ranges from −60 V to 60 V.