An efficiently enhanced UV-visible light photodetector with a Zn:NiO/p-Si isotype heterojunction

Abstract

A high-performance broadband photodetector based on a Zn-doped NiO/p-Si isotype heterojunction was successfully fabricated, which consisted of a Zn-doped NiO film on a Si substrate via a facile sol–gel method. The as-fabricated isotype heterojunction device displays an excellent broad-band (350–650 nm) detection performance with an outstanding external quantum efficiency (EQE) of 89.5% at a small reverse bias of −1 V and as high as ∼184% at −4 V. Moreover, the maximum photo–dark current ratio (switching ratio) of 1793% was achieved at −1 V under illumination with 650 nm light (0.5 mW cm⁻²); additionally, the response time of the as-fabricated device was less than 0.3 s. Such a high-performance of the Zn-doped NiO/p-Si isotype heterojunction photodetector guarantees its potential use in UV-visible low-voltage optoelectronic devices, especially for weak-signal detection and portable equipment.