Radiation resistance of near-infrared photodiodes based on Hg3In2Te6

The design and technology of photodiodes manufacturing with a potential barrier as Schottky contact based on a substrate of radiation-resistant n-Hg3In2Te6 single crystal are presented. The photosensitivity of the photodetector covers the wavelength range λ≈0.6-1.6 μm at the maximum current monochromatic sensitivity Sλ≈1.15 A/wt for the λmax≈1.55 μm. To study the effect of contact material on the effect of the absorbed dose of ionizing radiation, two types of photodetectors Ni/n-Hg3In2Te6/In and Cr/n-Hg3In2Te6/Cr were fabricated. A study of the effect of absorbed doses of ionizing radiation Dγ1≈105 , Dγ2≈106 і Dγ3≈107 Gray on the main parameters of photodetectors: Sλ, λmax, dark currents at forward and reverse bias, open circuit voltage, short circuit current. Photodiodes, based on mercury-indium telluride (HgInTe), showed high resistance to ionizing radiation. The best resistance to ionizing radiation was shown by Cr/HgInTe/Cr photodiodes, which slightly changed their basic parameters at the absorbed dose of Dγ3≈107 Gray. Ni/HgInTe/In photodetectors lost their function after exposure to an absorbed dose of Dγ3≈107 Gray. In Ni/HgInTe/In photodetectors the absorbed dose of Dγ3≈107 Gray practically destroyed the indium contact. 30-50 % of nickel front contact was also destroyed. For comparison, similar studies were performed with photodetectors based on cadmium telluride Cr/CdTe/In, prepared by the authors and silicon too. As silicon-based photodetectors the industrial photodiodes were used.