Tunable linearity of high-performance vertical dual-gate vdW phototransistor

TL;DR

This paper demonstrates a dual-gate WSe2 phototransistor that achieves tunable linearity and high responsivity by employing opposite dual-gating, enabling high-resolution light detection with layered 2D semiconductors.

Contribution

It introduces a dual-gate design in WSe2 that allows for tunable linear photoresponse and high responsivity, addressing the challenge of balancing high sensitivity and linearity.

Findings

Achieved a responsivity of ~2.5×10^4 A/W.

Maintained low 1/f noise, resulting in high detectivity (~2×10^13 Jones).

Enabled tunable linearity in the phototransistor's response.

Abstract

Layered two-dimensional (2D) semiconductors have been widely exploited in photodetectors due to their excellent electronic and optoelectronic properties. To improve their performance, photogating, photoconductive, photovoltaic, photothermoelectric, and other effects have been used in phototransistors and photodiodes made with 2D semiconductors or hybrid structures. However, it is difficult to achieve the desired high responsivity and linear photoresponse simultaneously in a monopolar conduction channel or a p-n junction. Here we present dual-channel conduction with ambipolar multilayer WSe2 by employing the device concept of dual-gate phototransistor, where p-type and n-type channels are produced in the same semiconductor using opposite dual-gating. It is possible to tune the photoconductive gain using a vertical electric field, so that the gain is constant with respect to the light intensity-a linear photoresponse, with a high responsivity of ~2.5*10^4 A/W. Additionally, the 1/f noise of the device is kept at a low level under the opposite dual-gating due to the reduction of current and carrier fluctuation, resulting in a high detectivity of ~2*10^13 Jones in the linear photoresponse regime. The linear photoresponse and high performance of our dual-gate WSe2 phototransistor offer the possibility of achieving high-resolution and quantitative light detection with layered 2D semiconductors.