UV to NIR photodetection in lateral homojunction PN diode of WSe2 achieved via IGZO sputtering

Abstract

Nano-devices based on two-dimensional (2D) semiconductor materials encourage the development of high-performance homogeneous junctions owing to their remarkable electronic and optoelectronic properties. Herein, we fabricated an atomically thin WSe2 (similar to 4.8 nm) lateral homojunction PN diode through the deposition of indium gallium zinc oxide (IGZO) via sputtering. Pristine WSe2 exhibited dominant p-type semiconductor behavior, while IGZO-deposited WSe2 demonstrated n-type behavior, revealing that IGZO altered the carrier polarity of WSe2 from p- to n-type. Furthermore, we investigated gate-dependent I-V curves of the lateral homojunction PN (p-WSe2/n-IGZO<middle dot>WSe2) diode in the dark based on a single WSe2 flake, which showed a promising current rectification ratio (similar to 1.6 x 104) and ideality factor (similar to 1.23) at VBG = -30 V, respectively. Subsequently, to explore the photodiode characteristics, we irradiated the lateral homojunction PN diode of WSe2 under ultra-violet (UV) to near-infrared (NIR) light (365, 530, and 850 nm). The I-V curves of the diode significantly changed under light irradiation, and the open circuit voltage (Voc = 202, 166, and 134 mV) and short circuit current (Isc = 320, 171, and 122 nA) values increased under illumination of a laser of small wavelength (365, 530, and 850 nm). Furthermore, we investigated the time-dependent photoresponse behavior of the diode under different laser lights. This demonstrated promising photoresponsivity (RPh = 40.1 A W-1) and external quantum efficiency (EQE = 13 634%) at lambda = 365 nm and VBG = 15 V. Hence, our lateral homojunction PN diode WSe2-IGZO/WSe2 shows great potential for next-generation electronic devices at the nanoscale level.