In this work ultraviolet metal-semiconductor-metal photodetectors with semitransparent Ni/Au interdigitated electrodes based on GaN/i-GaN/c-Al2O3 heterostructure were fabricated. The current-voltage, transient photoresponse on- off and spectral characteristics of the formed photodetectors were studied. It was found that the devices have a maximum responsivity at a wavelength of 364 nm with full width at half maximum of 11 nm, thus the presented PDs are narrowband.