Abstract
Specular CdTe films have been grown on (100), as well as 2°–6° off-oriented, Si substrates by low pressure metalorganic chemical vapor deposition method using dimethyl-cadmium (DMCd) and diethyl-telluride (DETe) as source materials. Growth temperatures range from 3450C to 4050C. 140K photoluminescence spectra show dominant sharp bound exciton related emission at 1.593 eV and weak defect related extrinsic band at 1.483 eV. The CdTe film grown at 375°C unity DMCd/DETe ratio has the lowest intensity ratio of I defect/I exciton. Sharp cubic phase structure with a preferential orientation of (111) is obtained for CdTe films grown at 355-375°C and for all 2°–6° off oriented (100) Si. Films grown at temperatures below 345°C and above 395°C exhibit x-ray diffraction patterns which contain extra hexagonal phase structures. Hall measurement and deep level transient spectroscopy are also used to characterize the electrical properties and defect levels of CdTe films. All grown CdTe are n-type with carrier concentration of about 1017cm -3 and mobilities of 500-600 cm 2 /V-sec at room temperature. Five levels, E c -0.15, 0.25, 0.34, 0.57 and 0.76 eV, are observed in the near interface region of n-CdTe/P + -Si heterojunction. © 1987, SPIE.