Room temperature persistent photoconductivity in p-PbTe and p-PbTe: BaF2

We investigated the persistent photoconductivity effect observed in p-PbTe: BaF2 and undoped p-PbTe films in the temperature range of T = 100-300 K. It was observed that the PPC effect scales with temperature and that there is a transition in the relaxation time behavior around similar to 150 K. We found that the transition is caused by the particular dynamics of the hole carries between the energy barriers that characterize the traps originated from disorder present in the samples. The analysis was performed by comparing the theory of the random potential with the experimental data and revealed the presence of both random local potential fluctuations and localized states, which can be attributed to the presence of disorder due BaF2 doping and Te vacancies. (C) 2014 AIP Publishing LLC.