All‐Oxide Transparent Photodetector Array for Ultrafast Response through Self‐Powered Excitonic Photovoltage Operation

Abstract

Can photodetectors be transparent and operate in self‐powered mode? Is it possible to achieve invisible electronics, independent of the external power supply system, for on‐site applications? Here, a ZnO/NiO heterojunction‐based high‐functional transparent ultraviolet (UV) photodetector operating in the self‐powered photovoltaic mode with outstanding responsivity and detectivity values of 6.9 A W−1 and 8.0 × 1012 Jones, respectively, is reported. The highest IUV/Idark value of 8.9 × 104 is attained at a wavelength of 385 nm, together with a very small dark current value of 9.15 × 10−12 A. A large‐scale sputtering method is adopted to deposit the heterostructure of n‐ZnO and p‐NiO sequentially. This deposition instinctively forms an abrupt junction, resulting in a high‐quality heterojunction device. Moreover, developing a ZnO/NiO‐heterojunction–based 4 × 5 matrix array with an output photovoltage of 4.5 V is preferred for integrating photodetectors into sensing and imaging systems. This transparent UV photodetector exhibits the fastest photo‐response time (83 ns) reported for array configurations, which is achieved using an exciton‐induced photovoltage based on a neutral donor–bound exciton. Overall, this study provides a simple method for achieving a high‐performance large‐scale transparent UV photodetector with a self‐powered array configuration.

A study of the optical properties of wide bandgap oxides for a transparent photovoltaics platform

“…The higher exciton binding energy of 60 meV allows excitons to persist in ZnO at room temperature. 39 The photo-to-dark current and response speed of TPV devices are summarized in Table 2.…”

“…The high degree of freedom of power supply has been demonstrated in the proof-of-concept selfpowered operation for broadband photodetection, 35 real-time wearable UV-radiation monitoring devices with a fast response, 36 smart artificial skin of thermoreceptors and memory, 21 subretinal functional devices for human-machine interface, 37 the visible light communication with onsite power and machine learning ability, 38 and its array integration for high-performance optoelectronics. 39 The primary objective of this study is to investigate how TPV device performance is affected by the optical properties of its component materials. Therefore, different heterojunctions are studied to find suitable combinations of materials and processing for improved TPV device performance.…”

“…The high degree of freedom of power supply has been demonstrated in the proof-of-concept self-powered operation for broadband photodetection, 35 real-time wearable UV-radiation monitoring devices with a fast response, 36 smart artificial skin of thermoreceptors and memory, 21 subretinal functional devices for human–machine interface, 37 the visible light communication with onsite power and machine learning ability, 38 and its array integration for high-performance optoelectronics. 39…”

2D Perovskite Single‐Crystalline Photodetector with Large Linear Dynamic Range for UV Weak‐Light Imaging

“…While other semiconductors such as nickel oxide and ZnO have wider band gaps, they exhibit limitations in terms of weak‐light detectable limit, LDR, and dark current density, which impact their suitability for UV weak‐light detection. [ 8,13,14 ] Therefore, there is a strong need to explore novel high‐performance PDs that can provide a low weak‐light detectable limit, broad LDR, high imaging quality, and can be manufactured using cost‐effective procedures and assembly techniques.…”

Oxygen Vacancies Mediated Co‐Sputtered Ti‐Doped BiVO4 Thin Films‐Based Transparent Photovoltaic Device

“…This work has chosen p‐type NiO for p‐type semiconductors to fabricate Ti:BiVO 4 ‐based TPV devices due to its suitable band alignment, high bandgap value (3.8 eV), transparency, and mobility. [ 38 ] The reactive magnetron co‐sputtering has been used to deposit the Ti:BiVO 4 and NiO layers due to better doping control, fast growth rate, and large‐scale production. [ 16,39 ] The sputtering power of Ti has been varied from 25 to 50 W during the co‐sputtering of Ti:BiVO 4 to control its structural, optical, and doping concentration by extrinsic doping effect.…”