Metal-Oxide-Semiconductor-Structured MgZnO Ultraviolet Photodetector with High Internal Gain

A Au/MgO/MgZnO metal-oxide-semiconductor-structured photodetector was fabricated. The responsivity of the photodetector was about 2 orders of magnitude larger than that of the Au/MgZnO metal-semiconductor-structured photodetector fabricated under the same procedure except that no MgO layer was introduced. The detectivity of the photodetector is about 1 order of magnitude larger than the corresponding value of Si photodetector that is widely employed for ultraviolet detection currently. The enhanced responsivity was attributed to the carrier multiplication occurring in the MgO layer via impact ionization. The results reported in this paper may provide a facile route to ultraviolet photodetectors with high internal gain.