Transparent conducting Ga 2 O 3 -In 2 O 3 thin films prepared by pulsed laser deposition using split targets

Abstract

The split target composed of Ga 2 O 3 and In 2 O 3 was used to deposit transparent conducting Ga-In oxide thin films on glass substrate by a pulsed laser deposition technique using an ArF laser (λ = 193 nm). In all experiments, a repetition rate of 1-20 Hz, an energy density of 0.4-2 J/cm 2, and irradiation time of 20-300 min were used. An optical transmittance of more than 80% in the wavelength region of 380-2700 nm and the lowest resistivity of 6.96×10 -4 Ω·cm, attributing to a high Hall mobility of 52.4 cm 2 /V·s and a low carrier concentration of 1.71×10 20 cm -3 were obtained for the 100-150 nm thick Ga-In oxide film with 23.3 wt% Ga content grown in oxygen at substrate temperature of 350 °C. The optical energy gap was estimated to be 4.0 eV (310 nm) by plotting the relationship of the direct transition type. The surface morphology packed densely with the ellipsoidal crystallites of axis length of 100-150 nm equal to film thickness was observed by high-resolution SEM.