Photoluminescence study on the effects of the surface of CdTe by surface passivation

The etching effects on the CdTe surface treated by the different chemical e tchants, such as 2% Br-methanol (BM) and 2% Br-20% latic acid in ethylene g lycol (BLE) solutions are studied by both photoluminescence (PL) and atomic force microscopy. After etching, the dielectric materials ZnS and CdZnTe a re used for the passivation of the CdTe surface. The PL studies of the CdTe surfaces passivated by the dielectrics are carried out, and the results ar e correlated with the value of the lifetime of the CdTe. The results show t hat the etching of CdTe surface by BLE solution yields the better surface c ondition for CdTe. The surface trap states of CdTe are reduced by the CdZnT e and ZnS passivant which results in the increase in the surface lifetime o f CdTe. (C) 1999 American Institute of Physics. [S0021-8979(99)00909-3].