Studies of point defects for annealed <TEX>$AgInS_{2}/GaAs$</TEX> epilayer

The <TEX>$AgInS_{2}$</TEX> epilayers with a chalcopyrite structure grown using a hot-wall epitaxy method have been confirmed to be a high quality crystal. From the optical absorption measurements, a temperature dependence of the energy band gap on <TEX>$AgInS_{2}/GaAs$</TEX> was found to be <TEX>$Eg(T)=2.1365eV-(9.89{ imes}10^{-3}eV)T^{2}/(2930+T)$</TEX>. After the as-grown <TEX>$AgInS_{2}/GaAs$</TEX> was annealed in Ag-, S-, and In-atmospheres, the origin of point defects of <TEX>$AgInS_{2}/GaAs$</TEX> has been investigated by using photoluminescence measurements at 10 K. The native defects of <TEX>$V_{Ag},;V_{S},;Ag_{int}$</TEX> and <TEX>$S_{int}$</TEX> obtained from photoluminescence measurements were classified as donors or accepters. It was concluded that the heat-treatment in the S-atmosphere converted <TEX>$AgInS_{2}/GaAs$</TEX> to an optical p-type. Also, it was confirmed that In in <TEX>$AgInS_{2}/GaAs$</TEX> did not form the native defects because In in <TEX>$AgInS_{2}$</TEX> did exist in the stable form.