HgCdTe All Semiconductor Schottky Photodiode (NOT PUBLISHED)

We have fabricated and demonstrated a novel HgCdTe photovoltaic detector based on an isotype heterojunction between n:Hg sub (0.54) Cd sub (0.46) Te and n:HgTe. The difficulty of forming p-n junctions in this material system by intentional impurity doping has hampered progress in HgCdTe photovoltaic detectors; but this problem is avoided in the present structure, which requires, instead, the formation of a high quality metallurgical interface between the HgTe and the HgCdTe. Molecular beam epitaxy was used for this purpose. These structures were grown on (100) GaAs substrates and consisted, in order of growth, of buffer layers on ZnTe (d=0.3microns) and semiinsulating CdTe (d=11.9microns), upon which were grown first a 2000angstrom thick HgTe layer and finally the 2.25micron thick Hg sub (0.54) Cd sub (0.46) Te. Hg sub (0.54 Cd sub (0.46) Te layers are both n-type.