Vacancy defects were investigated in a series of CdTe thin films grown by close-space sublimation. Variable-energy positron annihilation lifetime spectroscopy measurements, performed with a high-intensity positron beam, were used to profile polycrystalline films with varying grain size. These were obtained by changing the nitrogen pressure used during deposition. Two vacancy defects were detected, with positron lifetimes of 321 and 450ps. Density functional theory calculations supported the assignment of the first to the Cd vacancy and provided evidence that the second was the divacancy defect.

Vacancy Defects in CdTe Thin Films. D.J.Keeble, J.D.Major, L.Ravelli, W.Egger, K.Durose: Physical Review B, 2011, 84[17], 174122