Electrical conductivity and minority carrier diffusion in thermally oxidized PbTe thin films

Thermally oxidized 0.1 and 1 μm thick n-type PbTe:In films were studied in this work. Two main processes induced during the thermal treatment in oxygen atmosphere were identified. These are the formation of an oxide phase on the surface and generation of acceptor states of oxygen along grain boundaries inside a film. The latter process causes inversion of the type of electrical conductivity in PbTe from n to p. Electron beam-induced current (EBIC) measurements of minority electron diffusion length in oxidized 0.1 μm thick PbTe:In film showed diffusion length increase with increasing temperature similar to the wide band gap semiconductors.