Rapid thermal annealing effects in CdTe (111) thin films grown on GaAs (100) substrates

Photoluminescence (PL) and double crystal X-ray rocking curve (DCRC) measurements have been carried out to investigate the rapid thermal annealing (RTA) effects in CdTe (111) epilayers grown on GaAs (100) by molecular beam epitaxy. The result of the X-ray diffraction showed that the orientation of the grown CdTe films was the (111) orientation. The full width at half maximum (FWHM) of the DCRC for as-grown CdTe layer was 400 arcs. When RTA was performed at 550 degrees C, the FWHM of the DCRC for the CdTe layer decreased 265 arcs. The results of the PL spectra showed that the luminescence intensity of a bound exciton (D-0, X) for the CdTe/GaAs annealed at 550 degrees C was raised by as much as about 53 times in comparison to the as-grown CdTe. The relative intensity ratio between (D-0, X) and the luminescence related to the defects for the as-grown and the annealed CdTe decreased by a factor of 7.8. These results indicate that the crystallinity of the CdTe epilayers grown on GaAs (100) is improved by RTA and that the RTA CdTe films grown on Si can be used for applications as buffer layers for the growth of HgxCd1-xTe.