Advances in 2-5 micrometer (Hg, Cd)Te photodiodes

Detection of 2-5 micrometer infrared radiation is important both for earth resources and for thermal imaging applications. In this paper we present new results on 2-5µm (Hg, Cd)Te photodiode arrays. 2.1µm photodiodes achieve D* = 6.0 × 10¹⁰cm Hz^1/2/W at 300K and D* = 5.0 × 10¹²cm Hz^1/2/W at 193K. The photodiodes have surface leakage resistance greater than 1.0 × 10¹²Ω. The devices display no 1/f noise to less than 0.1 Hz and have response linear in signal power to better than 0.5 percent. Arrays display uniformity of responsivity within ± 3 percent. The diode saturation current is limited by generation-recombination in the depletion layer with an effective lifetime of 6.0 × 10^-8sec. 2.7µm photodiodes achieve D*λ= 1.0 × 10¹⁰cm Hz^1/2/W at 300K and D*λ= 5.0 × 10¹¹cm Hz^1/2/W at 193K. 4.8µm photodiodes achieve D*λ= 8.0 × 10¹⁰cm Hz^1/2/W at 170K and 2.0 × 10¹²cm Hz^1/2/W at 77K and zero background. This paper will present these recent data and compare them with theory.