Growth and characterization of CuAlSe 2(1 1 2)/GaAs(1 0 0) heteroepitaxial layers grown by hot wall epitaxy method

Abstract

The CuAlSe 2(1 1 2)/GaAs(1 0 0) heteroepitaxial layers were grown by the hot wall epitaxy (HWE) method. From the measurements of the Laue patterns and the double crystal X-ray diffraction, the CuAlSe 2 epilayer was confirmed to be the epitaxially grown layer along the 〈1 1 2〉 direction onto a GaAs (1 0 0) substrate. The Hall mobility and carrier density of the CuAlSe 2 epilayer at 293 K were estimated to be 295 cm 2/V s and 9.24×10 16 cm −3, respectively. This mobility is approximately one order higher than the reported value. From the temperature dependence of the Hall mobility, the scattering at a high-temperature range was mainly due to the acoustic mode of lattice vibration. The scattering at a low temperature was the most pronounced range due to the impurity effect. From the low-temperature photoluminescence experiment, we observed the sharp and intensive free-exciton peak at 2.7918 eV. Also, this peak existed far more in the short-wavelength region than 2.739 eV of free exciton measured from the epilayer grown by the metalorganic chemical vapor deposition (MOCVD). Consequently, these facts indicate that the CuAlSe 2 epilayers grown by the HWE method are higher quality crystals than those grown by MOCVD or other methods.