Silicon nanowire/TiO2 heterojunction acting as an efficient UV photodetector

Abstract

The development of energy-efficient, long-term optical energy detection systems has been prompted by the significant increase in global energy consumption and population over the last decade. UV photodetectors are among the energy detection systems that have attracted potential applications in society, science, and military defence. The research community is currently focused on the development of ultraviolet (UV) photodetectors due to the wide range of applications that photodetectors have in modern society. To achieve higher photosensitivity, a variety of wide-band gap nanomaterials were used for UV detection. Wide band gap semiconductors, such as TiO2, have unique optoelectronic properties that have led to a wide range of applications in sensors and optoelectronics. TiO2 have become more popular in a variety of consumer products due to their unique properties resulting from the reduction of material size from the macro to the nano scale. In recent years, there has been a lot of focus on the development of various methods for synthesising TiO2 nanomaterials as well as its application in various fields. The use of a hydrothermal process to obtain TiO2 nanomaterials allows for the development of new synthesis methods that feature, among other things, the ability to control properties, repeatability, reproducibility, short synthesis time, low cost, purity, and compliance with the eco-friendly approach criterion. The work is on metal assisted chemically etched at 60 °C temperature porous silicon nanowires. The etching time is optimized at 60 minutes. Important characterizations are carried out. FESEM image signifies uniform growth of silicon nanowires. Then a seeding layer is deposited on the silicon nanowire. After preparation of seeding layer porous SiNWs/TiO2 nanowire photodiode were prepared by a combination of hydrothermal synthesis. The goal of this thesis is to review the current state of the art in the hydrothermal synthesis of TiO2 nanomaterials by the variation in concentration of time variation. The introduction, properties of TiO2 nanomaterials, and new applications of TiO2 nanomaterials are presented in the first section of the thesis. Following that, the properties of the hydrothermal process, reactants, process parameters, and the synthesis mechanism are discussed. Gradually, it moves on to the various characterization instruments that are used, defining not only the basic principles but also their benefits. The final section of the thesis discusses the morphology of products and divides the characterization results into three categories: i) Optical properties through FTIR (Fourier transform infrared spectroscopy), ii) XRD (XRAY DIFFRACTOMETER), ii) Morphological properties through FESEM (Field emission scanning electron microscopy) and HRTEM, and iii) Electrical properties through I-V (Current-Voltage) characterization, which describes it as a perfect material for photodetection applications.