Studies of localized levels in HgCdTe grown on Si and CdZnTe substrates using metal-organic chemical vapor deposition

Localized levels in the iodine-doped n-type HgCdTe fabricated on Si and CdZ nTe substrates by metal-organic chemical vapor deposition are studied by Fo urier transform infrared spectroscopy (FT-IR) and Hall measurement. These s urface morphologies are observed by laser scanning microscopy (LSM). From t he temperature dependencies of mobility and carrier concentration obtained by Hall measurement, and of transmittance obtained by FT-IR, microstructura l defects, doped I and a Hg atom on the Te site are thought to be the origi ns of localized levels for HgCdTe frown on Si substrate. Many pits are obse rved by LSM, suggesting the existence of defects. On the other hand, a He a tom on a Te site is the most conceivable origin of localized levels for HgC dTe grown on CdZnTe substrate. Since the heavily doped I leads to the degen eration of HgCdTe, other origins of localized levels are masked and cannot be confirmed. In the MCT grown on CdZnTe, microstructural defects and Hg va cancies are ruled out as the major candidates for the origin of the localiz ed levels because of the high quality of HgCdTe.