DEPTH-RESOLVED CATHODOLUMINESCENCE STUDY OF ZN-X CD1-XSE EPILAYER GROWN ON (001)INP BY METAL-ORGANIC CHEMICAL-VAPOR PHASE DEPOSITION

Optical properties of zincblende structured ZnxCd1-xSe epilayer grown on InP by metal organic chemical vapor phase deposition at temperature s of 360, 400, and 440 degrees C are investigated with low temperature cathodoluminescence spectroscopy (CL). Both near band gap and deep le vel emissions are found for the samples grown at 400 degrees C and abo ve, but deep level emissions are absent for the sample grown at 360 de grees C. We conclude that the growth temperature should be kept below the temperature at which InP begins to decompose and diffusion of III- V constituents into the epilayer occurs. Evidence of this diffusion co mes from an analysis of depth resolved CL studies, which shows that th e deep level emissions occur mainly at the epilayer/substrate interfac e. By monitoring the ratio of the intensity of the deep level emission s to that of the near band emissions, we find that this ratio is large r for samples grown at high temperatures than those at low temperature s. Indium diffusion from the substrate into the epilayer is most likel y the source of these deep levels. (C) 1998 American Institute of Phys ics. [S0003-6951(98)02248-7].