Positron study of nonstoichiometric vacancies in As-grown p-PbTe single crystals

Positron lifetime measurements of PbTe single crystals grown by the vertical Bridgman and the travelling heater method were carried out in the temperature range between 10 and 300 K. After source-background corrections the lifetime spectra (measured for 5 hours) were analyzed assuming one or two exponential components. The temperature dependences of the parameters of the positron lifetime spectrum of p-PbTe are shown and results of lifetime measurements at 300 K are listed. Positron trapping in as-grown p-type PbTe is attributed to negatively charged Pb vacancies