Deep-ultraviolet transparent conductive β-Ga2O3 thin films

Abstract

Thin films of $\mathrm{\beta -}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ with an energy band gap of 4.9 eV were prepared on silica glass substrates by a pulsed-laser deposition method. N-type conductivity up to ∼1 S cm⁻¹ was obtained by Sn-ion doping and deposition under low ${\mathrm{O}}_{\mathrm{2}}$ partial pressure ${\text{(∼10}}^{\text{−5}} \mathrm{Pa})$ at substrate temperatures above 800 °C. The resulting internal transmittance at the wavelength (248 nm) of the KrF excimer laser exceeded 50% for the 100-nm-thick film, making this the most ultraviolet-transparent conductive oxide thin film to date and opening up prospects for applications such as ultraviolet transparent antistatic electric films in ultraviolet lithography.