Ultraviolet-assisted annealing for low-temperature solution-processed p-type gallium tin oxide (GTO) transparent semiconductor thin films

摘要

Solution-processed p-type gallium tin oxide (GTO) transparent semiconductor thin films were prepared at a low temperature of 300 degrees C using ultraviolet (UV)-assisted annealing instead of conventional high-temperature annealing (> 500 degrees C). We report the effects of UV irradiation time on the structural, optical, and electrical properties of sol-gel derived GTO thin films and a comparison study of the physical properties of UV -assisted annealed (UVA) and conventional thermally annealed (CTA) GTO thin films. The Ga doping content was fixed at 15 at% in the precursor solution ([Ga]/[Sn] + [Ga] = 15%). After a spin-coating and preheating procedure was performed two times, the dried sol-gel films were heated on a hotplate at 300 degrees C under IN light irradiation for 1-4 h. Each UVA GTO thin film had a dense microstructure and flat free surface and exhibited an average optical transmittance approaching 85.0%. The level of crystallinity, crystallite size, and hole concentration density of the GTO thin films increased with increasing UV irradiation time. In this study, the UVA 4 h thin film samples exhibited the highest hole concentration (9.87 x 10(17) cm(-3)) and the lowest resistivity (1.8 Omega cm) and had a hole mobility of 5.1 cm(2)/Vs.