Photoconductivity of CdS/sub x/Se/sub 1-x/ with controlled deviation from stoichiometry

Photoconductivity of Cd/sub 1+y/(S/sub x/Se/sub 1-x/) single crystals with controlled deviation from stoichiometry is studied. The deviation y from stoichiometry of the sample is controlled through the growth process or a heat treatment by regulating the sum of chalcogen partial pressure P/sub ps/ (= P/sub S2/ + P/sub Se2/), and by keeping the pressure ratio P/sub r/ (= P/sub S2/P/sub Se2/) constant in each experiment. The photoconductivity at room temperature and 85 K of high resistivity samples decreases rapidly with increasing P/sub ps/. From the results, it is found that the native defect such as Cd vacancy is created in the crystal through the stoichiometry control and its electrically neutral state acts as a recombination centre for photoconductivity. (author)