Extraordinary photoresponse in sub-5 nm 2D GaN tunneling field effect transistor for optical detection application

Abstract

We employ first-principles calculations to investigate the photoelectric properties and regulatory role of Tunneling Field Effect Transistor (TFET) with 5.1 nm two-dimensional (2D) GaN as channel material. The best photocurrent density and photoresponse could reach 4.42 mA/cm² and 13.3 mA/W, with an external quantum efficiency (EQE) of 8 % at 0.5 V bias voltage, -1.5 V gate voltage, and 6 eV energy. Moreover, the F atom adsorption could effectively enhance the photoelectric properties of GaN TFET, with the photocurrent density, photoresponse and EQE respectively up to 27.50 mA/cm², 83.1 mA/W and 49.8 %. Furthermore, by shortening channel length to 4.1 nm and 3.1 nm, the photoelectric performance of GaN TFET was not reduced. The peak photoresponse and the EQE of GaN TFET with 3.1 nm still respectively reach to 13.4 mA/W and 8.1 %. Such excellent photoresponse in 2D GaN-TFETs suggest a great potential for future optical detection and storage devices.