Optical and electrical properties of in situ-annealed p-type Hg_0.7Cd_0.3Te epilayers grown on CdTe buffer layers for applications as infrared detectors

Hall-effect, Fourier transform infrared (FTIR) transmission, and photopresponse measurements were performed to investigate the optical and electrical properties of as-grown and in situ-annealed Hg_0.7Cd_0.3Te epilayers grown on CdTe buffers on GaAs (211) B substrates layers by using molecular-beam epitaxy. Hall-effect measurements showed that as-grown n-Hg_0.7Cd_0.3Te epilayers were converted to p-Hg_0.7Cd_0.3Te epilayers due to in situ annealing. The carrier concentration and the mobility as functions of the annealing temperature were determined from the Hall-effect measurements. The FTIR spectra showed that the transmission intensity had increased in comparison to that of the as-grown Hg_0.7Cd_0.3Te epilayer. Hall-effect measurements showed that n-Hg_0.7Cd_0.3Te epilayers were converted to p-Hg_0.7Cd_0.3Te epilayers. The activation energy and the carrier lifetime of the annealed Hg_0.7Cd_0.3Te epilayer were 0.25 eV and 160 ns, respectively. These results indicate that p-type Hg_0.7Cd_0.3Te epilayers grown on CdTe buffer layers due to in situ thermal annealing hold promise for potential applications in infrared detector technologies. © 2003 American Institute of Physics.