Effect of ultraviolet radiation and electric field on the conductivity of structures based on $\alpha$- and $\varepsilon$-Ga$_{2}$O$_{3}$

The influence of ultraviolet radiation and a strong electric field on the current-voltage characteristic of resistive structures based on polymorphic films of gallium oxide is studied. Both types of Ga$_{2}$O$_{3}$ films were obtained by the method of chloride vapor-phase epitaxy on smooth and structured sapphire substrates with orientation (0001). In the same process $\alpha$-Ga$_{2}$O$_{3}$ films were deposited on smooth substrates, and gallium oxide films, with regular structures perpendicular to the substrate, containing alternating regions of the $\alpha$- and $\varepsilon$-phases were deposited on patterned substrate. It's was observed, that radiation with $\lambda$ = 254 nm and strong electric transfer structures from a state with low resistance to a state with high resistance. The response time to UV radiation is 5 seconds, and the recovery time less than 1 s.