p-GaSe/n-Ga₂O₃ van der Waals Heterostructure Photodetector at Solar-Blind Wavelengths with Ultrahigh Responsivity and Detectivity

Abstract

Ga2O3 with a suitable bandgap width is emerging to be a novel candidate for future optoelectronic applications in the solar-blind region (<280 nm). Herein, solar-blind photodetectors are developed by combining layered GaSe flakes with Ga2O3 epitaxial films, forming a van der Waals pn heterojunction. Photoresponse characterizations indicate that the GaSe/Ga2O3 pn junction is highly sensitive to solar-blind ultraviolet light, with the maximum sensitivity at ∼255 nm. The photodetector demonstrates a particularly high responsivity of 51.9 A/W, a pronounced specific detectivity up to 1014 Jones, and a fast response speed of ∼0.3 ms under ultraweak light illumination. These figures of merit are significantly superior to most of the reported Ga2O3-based photodetectors. This work reveals the great potential of GaSe/Ga2O3 van der Waals heterojunction for developing next-generation, solar-blind photodetectors.

Ultrahigh Gain Solar Blind Avalanche Photodetector Using an Amorphous Ga2O3-Based Heterojunction

“…Photoconductive PDs are endowed with large photoconductive gains but suffer from slow response speed because of the persistent photoconductivity effect. Schottky barrier PDs and heterojunction PDs have been demonstrated to be effective strategies to realize solar-blind UV photodetection with considerable performance, where a junction formed at the interface is in favor of promoting photogenerated electron/hole separation under UV light illumination, resulting in superior comprehensive properties. , Considering practical applications, the object UV signals are generally weak. Thus, both the responsivity and detectivity of solar-blind UV PDs should be further improved.…”

A self-powered high performance UV-Vis-NIR broadband photodetector based on β-Bi2O3 nanoparticles through defect engineering

“…Moreover, the responsivity decreases with increasing light power, which is attributed to the enhanced recombination of photo-generated carriers under higher light power illumination. 41,42 The specific detectivity ( D *) is also calculated using the following formula:In Fig. 6(e), a maximum specific detectivity of 7.46 × 10 10 Jones is obtained under a relatively weak light power of 5 mW cm −2 , which is higher than the previously reported β-Bi 2 O 3 /SnO 2 specific detectivity of 4.5 × 10 9 Jones.…”

“…Moreover, the responsivity decreases with increasing light power, which is attributed to the enhanced recombination of photo-generated carriers under higher light power illumination. 41,42 The specific detectivity (D*) is also calculated using the following formula:…”

Solution-processed transparent p-type orthorhombic K doped SnO films and their application in a phototransistor

“…4(f) and (g), the photogenerated current decreases swiftly with increasing V g (−15 to 15 V), demonstrating p type characteristics even under illumination at 600 nm and 900 nm. For further analyzing the performance of the photodetector, some key variables such as the responsivity ( R λ ) and detectivity ( D *) were evaluated using the following relations: 11,27,28 R λ = I ph / PS and D* = R λ /(2 eI dark / S ) 1/2 (where I ph = I light − I dark is the photocurrent, P is the incident light power intensity, S is the active area of the device (9 × 10 −8 m 2 ), and e stands for electron charge). Fig.…”