Photodiodes in thin films of epitaxial PbTe grown on BaF2have been fabricated using Sb+ion implantation to create ann‐type layer inp‐type films. At 77 °K, 15‐mil‐square diodes had typical zero‐bias resistances of 1 M&OHgr;. With the infrared radiation incident on then‐type implanted layer, peak detectivities at 5.3 &mgr;m of 4.5 &khgr; 1011cm Hz1/2/W were observed in reduced background. Quantum efficiencies were typically 55%. With the radiation incident on thep‐type side through the BaF2substrate, the detectivity was much more sharply peaked with the peak occurring at 5.5 &mgr;m. The peak detectivity and quantum efficiency values in this case were similar to those for incidence on then‐type implanted layer.