RAPID THERMAL ANNEALING EFFECTS IN CDTE(111) THIN-FILMS GROWN ON SI(100) SUBSTRATES BY MOLECULAR-BEAM EPITAXY

Photoluminescence (PL) measurements have been carried out to investiga te rapid thermal annealing (RTA) effects in CdTe(111) epilayers grown on Si(100) by molecular beam epitaxy. The full width at half maximum ( FWHM) of the bound exciton peak of the PL spectrum for the as-grown Cd Te layer was 20 meV. When RTA was performed at 400 degrees C, the boun d exciton peak was resolved into two bound exciton peaks due to neutra l accepters (A degrees, X) and to neutral donors (D degrees, X) and on e free exciton peak; the FWHM of the (A degrees, X) peak was as small as 3.7 meV. When RTA was carried out at 600 degrees C, the relative in tensity ratio between the luminescences related to the defects and (A degrees, X) in the as-grown and the annealed CdTe layers decreased by a factor of 15. The activation energy of the (A degrees, X) peak as ob tained from temperature-dependent PL measurements was 18.7 meV. The bo und exciton peak for the CdTe, which was rapidly thermally annealed at 400 degrees C, shifted by 7.5 meV in comparison with that for the CdT e bulk, and the strain obtained from the PL peak shift was -0.0286. Th ese results indicate that the crystallinity of the CdTe epilayers grow n on Si 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-xT e.