Effect of Neutron and γ‐Ray Irradiation on the Carrier Lifetime and Detectivity of InSb

Single crystals of p‐type InSb were irradiated by 4.5 MeV neutrons or γ‐rays at liquid nitrogen temperature. The damage produced by neutron irradiation resulted in a small decrease of the carrier lifetime and a large decrease of the detectivity of the crystal. The damage produced by γ‐rays resulted in an increase or decrease of lifetime, the change depending on how strongly p‐type the crystal was. The detectivity was decreased upon γ‐irradiation. Annealing experiments show that neutron damage is permanent while γ‐ray defects can be completely annihilated near or above room temperature, giving a similar result as electron irradiation. Analysis of the effects on lifetime and detectivity shows that neutron damage effects, although severe and permanent, produce no important decrease of lifetime.