High-performance 8—14- µm Pb1-xSnxTe photodiodes

Photovoltaic detectors of Pb1-xSnxTe, sensitive in the 8- 14-µm spectral region, with near-theoretical performance characteristics, have been fabricated by a surface inversion technique. These detectors have exhibited quantum efficiencies of up to 45 percent limited by surface reflection), zero-bias resistance-area products of 21 Ωċcm²and background-limited detectivities of 1.5 × 10¹¹cm ċ Hz^1/2/W. A theoretical model consistent with experimental results is presented. Such high-performance devices are useful in guidance, reconnaissance, surveillance, ranging, and communication systems.