Optical and electrical properties of solution grown zinc oxide

Abstract

Zinc Oxide has been attracting increasing attention in the recent years as a Transparent Conducting Oxide (TCO). It is being widely viewed as a material that could find potential use in solar cells in the future. In this project, a solution route was utilized to fabricate Zinc Oxide films. Undoped and Indium doped films were fabricated at the Institute of Materials Research and Engineering (IMRE). Post-growth annealing treatment was then done on different films in oxygen, nitrogen and vacuum environments at 200°C, 300°C, 400°C and 550°C for Undoped samples. Indium doped films were exposed to annealing temperatures 300°C, 400°C and 550°C in a vacuum environment. Characterization techniques such as x-ray Diffraction, Photoluminescence, Hall Measurements, Transmittance and Photoconductivity were used to understand the optical and electrical behavior of films. The results obtained in the report show that the vacuum environment is the most conducive environment for producing highly conductive films. Temperature played a dominant role in reducing surface defects in all films when they were annealed above 300°C. Indium doping increased film conductivity, transient response and decay but decreased material mobility. Changes in optical properties in films treated at various environment and temperature conditions were observed to be low. Based on the characterization results, the film doped with Indium and annealed at 400°C in vacuum environment was selected as the best candidate for application in solar cells.