The surface variation of ZnO nanorods via annealing with hydrogen gas and Oxygen gas

Abstract

In the past technology the wavelength used for ZnO nanorod photodetector was restricted to ultraviolet But in recent years people start to study how to use one-dimensional structures or porous materials to reduce the light reflectivity of the photoelectric system in solar cell field In a recent research it mentioned that ZnO nanorod can turn into porous ZnO nanorod through the process of argon/hydrogen annealing And the wavelength range of porous ZnO nanorod for photodetector can broaden to visible light We want to research whether the surface element of material changed by the Ar/H2 annealing is the reasons why the light reflectivity of porous ZnO nanorod can be reduced and the wavelength range of ZnO nanorod for photodetector can be broaden In this work we make these ZnO nanorod samples finishing the Ar/H2 annealing process and then we use scanning electron microscopy to observe the morphology of these samples We use photoluminescence spectroscopy to analyze what is the defect state in bulk of ZnO nanorod and use photoelectron spectroscopy to analyze what is the chemical state in surface of ZnO nanorod We will discuss how the argon gas and hydrogen gas change the morphology of ZnO nanorod the surface chemical state of ZnO nanorod and the defect state in the bulk of ZnO nanorod Then we try to let these samples annealed by Ar/H2 gases before do oxygen annealing to observe if oxygen can help repair the surface morphology and change the chemical state into the corresponding chemical state In the experiment we observe the anneal temperature and whether the anneal tube is a open system can have a great influence on the surface state of ZnO nanorod and the formation of porous morphology This work will explain how hydrogen argon oxygen change the surface element state of ZnO nanorod and the relation between the surface morphology the surface element state the surface adsorption And we also show which kind of Ar/H2 anneal condition the best porous ZnO nanorod produced in

Date of Award	2019
Original language	English
Supervisor	Kuang-Yao Lo (Supervisor)