CdHgTe heterostructures for new-generation IR photodetectors operating at elevated temperatures

The parameters of multilayer Cd$_{x}$Hg$_{1-x}$Te heterostructures for photodetectors operating at wavelengths of up to 5 $\mu$m, grown by molecular-beam epitaxy (MBE) on silicon substrates, are studied. The passivating properties of thin CdTe layers on the surface of these structures are analyzed by measuring the $C$–$V$ characteristics. The temperature dependences of the minority carrier lifetime in the photoabsorption layer after growth and thermal annealing are investigated. Samples of $p^{+}$–$n$-type photodiodes are fabricated by the implantation of arsenic ions into $n$-type layers, doped with In to a concentration of (1–5) $\times$ 10$^{15}$ см$^{-3}$. The temperature dependences of the reverse currents are measured at several bias voltages; these currents turn out to be almost two orders of magnitude lower than those for $n^{+}$–$p$-type diodes.