Impact of al and Sn doping and annealing upon morphology, wettability and optical properties of Ga2O3 films prepared by spray pyrolysis

Abstract

In this work, a cost-effective technological approach was developed for preparation of Ga2O3 films, using a spray pyrolysis method. Undoped Ga2O3 films, as well as 3% Sn and Al doped Ga2O3 films subjected to thermal treatment at 800°C, or 930°C were used for this study. The obtained films were characterized by atomic force microscopy (AFM) to study the topology and to determine their roughness. Optical properties (transmission and reflection spectra) were studied to determine the material bandgap from the Tauc plot and they were explained in terms of the formation of large band tails in the density of states of the produced films due to local potential fluctuations induced by doping. The contact angle of a 3 μL droplet of distilled water on the surface of each Ga2O3 film was measured for investigation of hydrophobic and hydrophilic properties of films surfaces. It was found that the films doped with Al have a larger roughness as compared to the undoped films, while those doped with Sn demonstrated a decreased roughness. The influence of thermal processing and doping on the hydrophobic properties of the produced films was deduced from contact angles measurements.