Influence of electrode topology on the parameters of solar-blind UV detectors

The influence of electrode topology on the electrical and photoelectric characteristics of metal/semiconductor/metal structures was investigated. Gallium oxide films were obtained by radio-frequency sputtering of a Ga$_2$O$_3$ target onto sapphire substrates with the (0001) orientation. Two types of electrodes were formed on the surface of the oxide films: two parallel electrodes with an interelectrode distance of 250 mkm and interdigitated ones. The distance between the “fingers” of the detectors of the second type was 50, 30, 10, and 5 mkm. Regardless of the type of contacts, the structures exhibit sensitivity to ultraviolet radiation with a wavelength of $\lambda$ = 254 nm. Detectors of the second type with an interelectrode distance of 5 $\mu$m demonstrate the highest values of the photocurrent $I_{\mathrm{ph}}$ = 3.8 mA and detectivity $D^*$ = 5.54 $\times$ 10$^{15}$ cm Hz$^{0.5}$W$^{-1}$.