ABSTRACT
CuGaSe2/GaAs(001) heteroepitaxial layers grown by metalorganic vapour phase epitaxy (MOVPE) were investigated focusing on structural and optical properties. Intentional disturbance of the interface during the initial stages of the MOVPE growth process led to a noticeable decrease of the epilayer quality analyzed by X-ray diffraction (XRD). Comparison of temperature-dependent photoluminescence (PL) of CuGaSe2 single crystals and different CuGaSe2 epilayers showed the effect of strain and strain relaxation present in the epitaxially grown layers. At 10 K a redshift of the near band edge luminescence as large as 22 meV compared to unstrained bulk crystals was observed. This observation is discussed in terms of the increase of strain, i. e. tetragonal distortion with decreasing temperature.
