Trap-assisted space charge limited transport in short channel MoS2 transistor

TL;DR

This study investigates high-bias conduction in short channel MoS2 transistors, revealing trap-assisted space charge limited transport, an exponential trap distribution, and a temperature-independent critical voltage, advancing understanding of their charge transport mechanisms.

Contribution

It provides a quantitative analysis of trap states and their role in space charge limited conduction in MoS2 transistors, which is a novel insight.

Findings

Conduction becomes space charge limited at high bias

Exponential trap state distribution observed

Critical drain-source voltage is temperature independent

Abstract

We present temperature dependent $I-V$ measurements of short channel MoS$_2$ field effect devices at high source-drain bias. We find that although the $I-V$ characteristics are Ohmic at low bias, the conduction becomes space charge limited at high $V_{DS}$ and existence of an exponential distribution of trap states was observed. The temperature independent critical drain-source voltage ($V_c$) was also determined. The density of trap states was quantitatively calculated from $V_c$. The possible origin of exponential trap distribution in these devices is also discussed.