LAUSR

IR photodetectors have been made on Pb/δ-layer/p-Pb1 –xSnxTe1 –ySey/p+-Pb0.8Sn0.2Te/Au and Au/δ-layer/n-Pb1 –xSnxTe1 –ySey(BaF2)/Pb surface-barrier structures prepared by liquid-phase epitaxy and thermal evaporation. At ~170 K, peak wavelength λp ~ 7.9–8.2 μm, and cutoff wavelength λc ~ 8.2–8.5 μm, the former surface-barrier structure has product R0A (where R0 is the zero-bias differential resistance and A is the active surface area) = 0.31–0.97 Ω cm2, peak quantum efficiency ηλ = 0.32–0.48, and specific detectability $$D_{\lambda }^{*}$$ = (0.72–1.83) × 1010 cm Hz1/2 W–1. For photodiodes made on the latter surface-barrier structure, these parameters measured at ~80 K are R0A = 1.71–2.72 Ω cm2, ηλ = 0.34–0.49, and $$D_{\lambda }^{*}$$ = (3.02–4.51) × 1010 cm Hz1/2 W–1 at λp ~ 8.6–12.3 μm and λc ~ 9.2–12.9 μm.