Thin Films of Zinc-Doped GaAs by RF Magnetron Sputtering for Use in Photovoltaic Cells

Radio frequency (RF) magnetron sputtering parameters that produce highly crystalline thin films of gallium arsenide (GaAs) were investigated. Literature results were reproduced to determine optimum conditions for sputtering highly crystalline films. At these desirable conditions, a noticeable increase in the Ga:As ratio was discovered, resulting from metallic gallium present on the film surface. A simple HCl treatment was developed to remove the excess gallium and return the film to the stoichiometric ratio of Ga:As. An in-situ zinc doping method was investigated and refined to sputter p-type GaAs films. Hall effect measurements confirmed that the Zn-doped films were p-type and the hole concentration increased with increasing Zn content.