The nature and behavior of the persistent photoconductivity in CdTe-In films which had been grown by co-sputtering CdTe-In-Cd targets were studied. It was found that the persistent photoconductivity, with a quenching temperature of about 270K, was observed only when In atoms were substantially incorporated into CdTe films. Thermally stimulated conductivity techniques revealed 2 localized deep levels. One, with an activation energy of 0.42eV, was attributed to DX centers that were formed from Cd vacancies and In donor complexes. The persistent photoconductivity effect was attributed to photo-ionization of this deep level. The existence of DX centers in CdTe-In polycrystalline films had not been previously reported.

DX Centers and Persistent Photoconductivity in CdTe-In Films Z.Rivera-Alvarez, L.Hernández, M.Becerril, A.Picos-Vega, O.Zelaya-Angel, R.Ramírez-Bon, J.R.Vargus-García: Solid State Communications, 2000, 113[11], 621-5