Band-gap tunable (GaxIn1−x)2O3 layer grown by magnetron sputtering

Multicomponent oxide (Ga x In 1− x ) 2 O 3 films are prepared on (0001) sapphire substrates to realize a tunable band-gap by magnetron sputtering technology followed by thermal annealing. The optical properties and band structure evolution over the whole range of compositions in ternary compounds (Ga x In 1− x ) 2 O 3 are investigated in detail. The X-ray diffraction spectra clearly indicate that (Ga x In 1− x ) 2 O 3 films with Ga content varying from 0.11 to 0.55 have both cubic and monoclinic structures, and that for films with Ga content higher than 0.74, only the monoclinic structure appears. The transmittance of all films is greater than 86% in the visible range with sharp absorption edges and clear fringes. In addition, a blue shift of ultraviolet absorption edges from 380 to 250 nm is noted with increasing Ga content, indicating increasing band-gap energy from 3.61 to 4.64 eV. The experimental results lay a foundation for the application of transparent conductive compound (Ga x In 1− x ) 2 O 3 thin films in photoelectric and photovoltaic industry, especially in display, light-emitting diode, and solar cell applications.