HgCdTe All Epitaxial Semiconductor/Semimetal Schottky Photodiode.

We propose and demonstrate an all epitaxial semiconductor/semimetal Schottky (S sup 3) photodiode based on an n-type Hg sub (0. 56) Cd sub (0.46)Te/HgTe isotype heterojunction. The structure, grown using molecular beam epitaxy, was fabricated into back- illuminated mesa diodes. A 40microns diameter photodiode shows room temperature rectification and high efficiency photoresponse, with a long wavelength cutoff of 2.43microns and a peak quantum efficiency of 44% at 2.0microns for 250 mV of reverse bias. The dark current at this bias is 100micronA.