Ultraviolet photoresponse of surface acoustic wave device based on Fe-doped high-resistivity GaN

The ultraviolet (UV) photoresponse of a surface acoustic wave (SAW) device fabricated on an Fe-doped high-resistivity GaN epitaxial film grown by hydride vapor phase epitaxy is investigated. The SAW device exhibits large variations in transmission characteristics under UV illumination, but shows a very low recovery rate after ceasing the illumination. Through the characterization of photocurrent and the simulation of the displacement field of Rayleigh wave, it is suggested that the persistent photoconductivity of the Fe-doped GaN is the origin of the retarded photoresponse of the SAW device, and that the wide surface depletion layer contributes to the large photoresponse of the SAW device.