Abstract
In these studies, deep level transient spectroscopy (DLTS) techniques and photoconductivity were used to investigate deep electron states in n-type Al-doped ZnSi_1-xTe_x with x=0, 1.86%, 2.5% and 5.7%. Two Al induced deep levels found in ZnS with energy 0.21 and 0.39 below the conductivity band. An additional deep state found in ZnSTe, which is 0.28 below the conduction band, is related to Te atom. Photoconductivity decay of Al-dopes ZnS and ZnSTe after illumination shows slow recovery of the resistance, indicating that the persistent photoconductivity (PPC) effect is present in both materials. Beside, for some short wavelength of excitation, the PPC was even observed at room temperature.