Design and calculation of photoelectric properties of type-II superlattice photodetectors with diffraction ring structure

Abstract

The photoelectric properties of type-II superlattices (T2SLs) infrared detectors with diffraction ring resonance structure are calculated and studied in this paper. In order to improve the quantum efficiency (QE), diffraction rings are designed on the top surface of T2SLs detectors to control the incident light inside. The maximum QE of ordinary detector is about 30%, while the detector with square diffraction rings is about 80%, and the detector with circular diffraction rings is about 60%. It shows that the structures with diffraction ring can significantly improve the QE of photodetectors. In addition, the size and shape of the resonator are studied. it is obvious that the optimization effect of the square diffraction ring is better than that of the circular diffraction ring, and the square diffraction ring is insensitive to the size change, so it is suitable for the manufacture of practical photodetectors. At the same time, the dark current mechanism of the detector is analyzed and the corresponding specific detectivity is calculated. Keyword: type-II superlattices; diffraction ring; resonant cavity; quantum efficiency