Laser Irradiation Effect on the p-GaSe/n-HfS₂ PN-Heterojunction for High-Performance Phototransistors

Abstract

Two-dimensional (2D)-based PN-heterojunction revealed a promising future of atomically thin optoelectronics with diverse functionalities in different environments. Herein, we reported a p-GaSe/n-HfS2 van der Waals (vdW) heterostructure for high-performance photodetectors and investigated the laser irradiation effect on the fabricated device. The fabricated 2D vdW heterostructure revealed a high photoresponsivity of 1 × 104 A W–1 with a photocurrent value of 377 nA due to unique type-II band alignment and enhanced surface potential under light illumination, which is further confirmed by density functional theory (DFT) calculations. Before laser irradiation, the device showed high field-effect mobility (μEF) of 26.37 cm2 V–1 s–1, ON/OFF ratio of ∼105, and threshold voltage swing (SS) of ∼463 mV dec–1. With the exposure of 690 mW cm–2 laser power density, μEF reached 204 cm2 V–1 s–1, although ∼2 V ΔV th shifts are observed along with the SS decreased to 175 mV dec–1. Interestingly, the reduced SS shows better channel control of the fabricated device with laser power. Similarly, the ON/OFF ratio decreased to ∼1.29 × 103. The results indicate that the creation of oxide trap charges at the interface of SiO2 and PN-heterojunction layers was observed with voltage biasing and high laser power density. The degradation of electrical parameters is attributed to fewer interface trap charges per surface area of the device rather than direct damage in PN-heterojunction layers. Considering the excellent 2D electronic properties, these materials are better candidates for future high-radiation environments.

Progress and Insight of Van der Waals Heterostructures Containing Interlayer Transition for Near Infrared Photodetectors

“…This report indicates that high power laser irradiation has also significant effect for tunning the semiconducting devices. [ 121 ] 2D vdWs heterostructures not only considered for developing the FETs devices but also are worthy choice to construct other potential electronic devices such as memristor based neuromorphic devices. Memristor based neuromorphic computing that have following conditions for developments; (1) fast switching, (2) high density integration and (3) energy efficient.…”

“…(c,d) Reproduced with permission. [ 121 ] Copyright 2022, American Chemical Society. e) Schematic diagram of Ag/SnS/Pt based memristor f) Electro‐optical characteristics of device under 4 V/1.5 ns voltage pulse.…”

“…d) Linear and log scale of transfer curve of GaSe/HfS 2 device. (c,d) Reproduced with permission [121]. Copyright 2022, American Chemical Society.…”

High‐Performance Infrared Photodetectors Driven by Interlayer Exciton in a Van Der Waals Epitaxy Grown HfS2/MoS2 Vertical Heterojunction

“…In addition, the conduction band edge of HfS 2 is located at 5.2 eV which is a large value compared with other TMDs. [27,28] Therefore, the difference between the conduction band edge of HfS 2 and the valence band edge of MoS 2 is small, enabling the formation of an interlayer bandgap that is sufficiently narrow for IR detection. [26,28] Furthermore, the significant contribution of the built-in potential within the HfS 2 /MoS 2 heterojunction was instrumental in achieving exceptional photoresponse in the HfS 2 /MoS 2 photodetector.…”

Radiation‐Tolerant Electronic Devices Using Wide Bandgap Semiconductors

“…Efforts to address these issues have been underway over the past two decades. Substantial progress has also been made in designing radiation‐hard thin films transistors (TFTs) with ZnO, Ga 2 O 3 , In 2 O 3 , SnO 2 , IGZO, SiC, GaN, and many other WBGs, [ 17–50 ] which are used in the CMOS integrated circuits (ICs) over a long period under various radiations. Emerging memory technologies were also developed to stabilize the data storage performance in high temperatures and extremely harsh environments.…”