High Hole Mobility van der Waals Junction Field-Effect Transistors Based on Te/GaAs for Multimode Photodetection and Logic Applications.

Abstract

Recently, interface scattering and low mobility have significantly impeded the performance of two-dimensional (2D) P-type transistors. 2D semiconductor tellurium (Te) has garnered significant interest owing to its unique atomic chain crystal structure, which confers ultrahigh hole mobility. van der Waals heterojunction enhances transistor performance by reducing scattering at the gate-channel interface, attributed to its high-quality interface. In this study, we present Te/gallium arsenide (GaAs) hybrid dimensional JFETs exhibiting sizable on-state currents, elevated transconductance, and mobility as high as 328.4 cm²V^-1s^-1. Achieving a low-power device, we lowered the threshold voltage from 1.9 to 1 V by modifying the carrier concentration of the gate. Furthermore, enhancing negative photoconductivity on the Te surface is achieved by tuning the depth of the channel depletion region, thereby achieving an enhanced negative photoconductivity mechanism with universal applicability. Based on this, a photodetector featuring both positive and negative photoconductivity and a photovoltaic effect was developed. The negative photoresponsivity and detectivity at 635 nm of the device are -64 AW^-1 and 1.41 × 10¹⁰ Jones, respectively. Utilizing these properties, we develop Te/GaAs JFET-based logic gate circuits and single-point negative photoconductive imaging applications. This provides a potential research avenue for future logic circuits and optoelectronic devices.