HgCdTe/CdTe heterostructure diodes and mosaics

This paper discusses the results of a study of the properties of HgCdTe/CdTe heterostructure diodes and mosaics. In this study, p-type HgCdTe epi-layers on the order of 20 µm were grown on CdTe substrates by a liquid-phase epitaxial (LPE) technique. These layers normally had a carrier concentration of 5 × 10¹⁶/cm³and a mobility of 400 cm²/V . s at 77 K. The n⁺-p junction was formed by boron ion implantation, and standard photolithographic techniques were used for the device fabrication. The diodes with no antireflection coating had a typical quantum efficiency of 40 percent. The 1/ noise knee was on the order of 10 Hz at zero bias. Surface leakage seemed to be the dominant component for diodes at temperatures less than 77 K. From mosaic studies, it was found that the spectral spread was less than ±0.3 µm for an area as large as 12 × 20 mm. The study indicates that LPE offers a viable technique for producing high-quality HgCdTe epi-layers on CdTe.