UV detectors based on In2O3Ga2O3 composite films

The photoelectric and structural properties of In
₂
O
₃
-Ga
₂
O
₃
composite films deposited by halide vapor phase epitaxy on sapphire substrates were investigated. The deposited films were a composite of cubic c-In
₂
O
₃
and δ-Ga
₂
O
₃
phases with a low content (In
_x
Ga
_1-x
)
₂
O
_2.4
solid solution deficient in oxygen phase at the surface region. The spectral dependencies of the responsivity, external quantum efficiency and detectivity were studied in the wavelength interval from 205 nm to 360 nm. The In
₂
O
₃
-Ga
₂
O
₃
composite films demonstrated high photosensitivity, low base resistance and wide spectral interval of sensitivity including UV-C, UV-B and UV-A wavelength ranges. The maximum external quantum efficiency and responsivity of the In
₂
O
₃
-Ga
₂
O
₃
composite films achieved under radiation exposure at a wavelength of 214 nm and electric field strength of 1 kV/cm were 3.8×10
⁵
% and 660 A/W, respectively. A mechanism for the high photosensitivity of the In
₂
O
₃
-Ga
₂
O
₃
composite films based on the bipolar generation of charge carriers mainly in the segregated regions of the δ-Ga
₂
O
₃
phase is proposed.