Photodiodes fabricated in epitaxial PbTe by Sb+ ion implantation

Abstract

Photodiodes in thin films of epitaxial PbTe grown on BaF₂ have been fabricated using Sb⁺ ion implantation to create an n‐type layer in p‐type films. At 77 °K, 15‐mil‐square diodes had typical zero‐bias resistances of 1 MΩ. With the infrared radiation incident on the n‐type implanted layer, peak detectivities at 5.3 μm of 4.5 χ 10¹¹ cm Hz^1/2/W were observed in reduced background. Quantum efficiencies were typically 55%. With the radiation incident on the p‐type side through the BaF₂ substrate, the detectivity was much more sharply peaked with the peak occurring at 5.5 μm. The peak detectivity and quantum efficiency values in this case were similar to those for incidence on the n‐type implanted layer.