Photoelectric characteristics of HgCdTe with Au-doping

Au-doping is one of the approaches to improve the performance of HgCdTe photovoltaic infrared detectors. The minority-carrier lifetime and diffusion length in HgCdTe could be improved by replacing the intrinsic Hg-vacancy with the doped Au. The Au-doping HgCdTe films were grown by liquid phase epitaxy method. The concentration of the doped Au was about 8×10¹⁵/cm³. A Hg-rich annealing technique was applied to suppress the Hg vacancies in the film and the Hg-vacancy concentration of 1-2×10¹⁵/cm³ could be achieved. The acceptor energy level in the annealed material was 8-12 meV measured by the temperature dependent Hall method, which was related to the annealing condition. The IR Focal Plane Array(IRFPA) of 14 µm cut-off wavelength was fabricated using the combination of Au-doping material and Ion-implanting technique. The results show that the replacement of Hg-vacancy with Au will greatly increase the responsivity of the detector and the inner quantum efficiency of the detector could exceed 95%.