TiO₂ Nanorod Arrays Based Self-Powered UV Photodetector: Heterojunction with NiO Nanoflakes and Enhanced UV Photoresponse

Abstract

The self-powered ultraviolet photodetectors (UV PDs) have attracted increasing attention due to their potential applications without consuming any external power. It is important to obtain the high-performance self-powered UV PDs by a simple method for the practical application. Herein, TiO nanorod arrays (NRs) were synthesized by hydrothermal method, which were integrated with p-type NiO nanoflakes to realize a high performance pn heterojunction for the efficient UV photodetection. TiO thin film can improve the morphological and carrier transport properties of TiO NRs and decrease the surface and defect states, resulting in the enhanced photocurrent of the devices. NiO/TiO nanostructural heterojunctions show excellent rectifying characteristics (rectification ratio of 2.52 × 10 and 1.45 × 10 for NiO/TiO NRs and NiO/TiO NRs/TiO , respectively) with a very low reverse saturation current. The PDs based on the heterojunctions exhibit good spectral selectivity, high photoresponsivity, and fast response and recovery speeds without external applied bias under the weak light radiation. The devices demonstrate good stability and repeatability under UV light radiation. The self-powered performance could be attributed to the proper built-in electric field of the heterojunction. TiO NRs and NiO nanoflakes construct the well-aligned energy-band structure. The enhanced responsivity and detectivity for the devices with TiO thin films is related to the increased interfacial charge separation efficiency, reduced carrier recombination, and relatively good electron transport of TiO NRs.

High‐Performance Flexible Self‐Powered Photodetector Based on Perovskite and Low‐Temperature Processed In2S3 Nanoflake Film

“…As an alternative, the semiconductor junctions (p–i–n, Schottky, Type II, etc.) can also achieve self‐powered photodetection by exploiting the photovoltaic effect . Due to the disequilibrium of charge concentrations and Fermi level in each layer, the built‐in electric field is formed at the junction interface.…”

Interfacial Passivation and Energy Level Alignment Regulation for Self‐Powered Perovskite Photodetectors with Enhanced Performance and Stability

“…As a light harvesting material, the perovskite layer absorbs photons to generate multiple electron-hole pairs that are separated and extracted by the respective ETL and HTL, thus producing net photocurrent without external bias. [8][9][10][11][12] The film quality of perovskite layer is crucial to the overall photoresponse performance of PPDs. [13][14][15] Nevertheless, during the crystallization process of solutionprocessed perovskite, heterogeneous nucleation and growth would result in abundant pinholes and cracks nearby grain boundaries, deteriorating the film quality.…”

Chế Tạo Linh Kiện Nhạy Quang Vùng Bước Sóng Uv Bằng Phương Pháp Dung Dịch Dựa Trên Tiếp Xúc Dị Thể P-N Từ Các Vật Liệu Tio2, Nio Và Các-Bon

“…Vật liệu TiO2 là bán dẫn loại n có xu hướng hấp thụ năng lượng photon và hình thành các electron tự do [8]- [10]. Bên cạnh TiO2, vật liệu NiO là bán dẫn loại p cũng được sử dụng rộng rãi nhờ độ linh động hạt tải cao và chi phí sản xuất thấp [11]. Gần đây, Nguyễn và các đồng sự đã chế tạo linh kiện nhạy quang tự cấp nguồn dựa trên tiếp xúc di thể TiO2/NiO.…”