Band-gap tunable (Ga_xIn_1-x)₂O₃ layer grown by magnetron sputtering

Abstract

Multicomponent oxide (Ga_xIn_1-x)₂O₃ 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_xIn_1-x)₂O₃ are investigated in detail. The X-ray diffraction spectra clearly indicate that (Ga_xIn_1-x)₂O₃ 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_xIn_1-x)₂O₃ thin films in photoelectric and photovoltaic industry, especially in display, light-emitting diode, and solar cell applications.

Keywords

(Ga_xIn_1-x)₂O₃ films / Band-gap tunable / Magnetron sputtering

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2021 Zhejiang University Press