Self-Powered Photoelectrochemical (Al,Ga)N Photodetector with an Ultrahigh Ultraviolet/Visible Reject Ratio and a Quasi-Invisible Functionality for 360° Omnidirectional Detection

Abstract

Self-powered ultraviolet (UV) photodetectors (PDs) are promising and essential for the applications of next-generation optoelectronic devices. This work proposes and demonstrates a self-powered photoelectrochemical (PEC) PD with three excellent characteristics successfully, which are the ultrahigh transmissivity, ultrahigh UV/visible reject ratio and responsivity. Thanks to the ultrahigh transmissivity, the PD can achieve the critical factor of quasi-invisible functionality to realize the 360° omnidirectional detection. Due to the angle-dependent photoresponsivity, this PEC PD can be utilized for quickly identifying the light direction. Furthermore, as the epitaxial substrate can have a nonignorable visible response, the key reason for obtaining the ultrahigh UV/visible reject ratio and excellent detection selectivity should be the removal of the epitaxial substrate. It is also found that the SiO2 layer can significantly enhance the photoresponsivity by suppressing the leakage current. With a demonstrated high stability, this PD would enable a broad range of optoelectronic applications, including 360° omnidirectional detection and UV communication.

Advances in Self-Powered Ultraviolet Photodetectors Based on P-N Heterojunction Low-Dimensional Nanostructures

“…However, a high density of dislocations and other structural defects hinders their use. In the future, improving the crystallization quality of AlGaN will still be an important way to promote the performance of AlGaN-based UV photodetectors [ 102 , 103 ].…”

Flexible Self‐Powered Photoelectrochemical Photodetector with Ultrahigh Detectivity, Ultraviolet/Visible Reject Ratio, Stability, and a Quasi‐Invisible Functionality Based on Lift‐Off Vertical (Al,Ga)N Nanowires

“…[1][2] In addition to the continuously adjustable bandgap within the UV range and the ability of shielding the visible light interference without any special filters, (Al,Ga)N material is an ideal material for making the PEC UV PDs. [1][2]17] Moreover, vertical (Al,Ga)N nanowires (NWs) are particularly suitable for PDs owing to their larger surface-to-volume ratio and effective optical coupling, increasing the optical absorption and photogenerated carrier density. [1][2][17][18][19] However, (Al,Ga)N material is mostly grown on the rigid substrates, such as sapphire and Si, which cannot meet the requirements for flexible devices.…”

“…Thanks to the ability for long-time working independently without energy consumption, self-powered photodetectors (PDs) can be the indispensable devices to make the detection systems economical and simple. [2,4,6] As the crucial components in the detection system, ultraviolet (UV) PDs are required for the wide applications in UV communication, fire warning, high-voltage corona detection, and ozone-hole monitoring. [1][2] Therefore, self-powered UV PDs with high flexibility and invisible functionality are pretty promising and necessary for the nextgeneration optoelectronic devices.Up to now, some research groups have developed the labor-less self-assembly approaches of fabricating the PDs and sensors requiring low power consumption.…”

“…[2,4,6] As the crucial components in the detection system, ultraviolet (UV) PDs are required for the wide applications in UV communication, fire warning, high-voltage corona detection, and ozone-hole monitoring. [1][2] Therefore, self-powered UV PDs with high flexibility and invisible functionality are pretty promising and necessary for the nextgeneration optoelectronic devices.…”

Expansion of the response range of photoelectrochemical UV detector using an ITO/Ag-nanowire/quartz UV-visible transparent conductive electrode

“…5 They have advantages over photoconductive-type detectors, such as fast response, and being self-powered and environment-independent. [6][7][8][9] For the PEC UV detector, its detection principle is mainly to use the built-in potential at the solid/liquid interface as the driving force to separate the photoelectric couple and generate photocurrent. 10 In recent years, researchers have conducted extensive research on PEC UV detectors in terms of the device structure, photoanode materials, carrier regulation, etc.…”