Deep ultraviolet photodetectors based on the In$_2$O$_3$–Ga$_2$O$_3$ mixed compounds films

The photoelectrical characteristics of the In$_2$O$_3$–Ga$_2$O$_3$ mixed compounds films grown by halide vapor- phase epitaxy on sapphire substrates were studied. The studied films were a mixture of cubic $\delta$-Ga$_2$O$_3$ and $c$-In$_2$O$_3$ phases. The obtained results for In$_2$O$_3$–Ga$_2$O$_3$ mixed compounds, $\varepsilon(\kappa)$-Ga$_2$O$_3$ and $c$-In$_2$O$_3$ films grown at similar conditions were compared. The In$_2$O$_3$–Ga$_2$O$_3$ mixed compounds films demonstrated the highest photosensitivity, operation rate and a low base resistance. The quan- tum efficiency was 6.9 $\cdot$ 10$^3$% at an electric-field strength of 1 kV/cm, which was significantly higher than in the known literature. It is assumed, that the high photosensitivity was caused by the generation of charge carriers in the $\delta$-Ga$_2$O$_3$ regions formed between $c$-In$_2$O$_3$ with a high electron concentration.