Structural and optical properties of In_xGa_(1-x)As strained layers grown on GaAs substrates by MOVPE

摘要

In_Ga_(1-x)As/GaAs pseudomorphic structures were grown by metalorganic vapor phase epitaxy. Reciprocal space mapping were recorded in the vicinity of (0 0 4) and (1 1 5) nodes using high resolution X-ray diffraction (HRXRD) in order to determine strain tensor components, indium compositions and thicknesses of alloys. Near-infrared photoluminescence (PL) was performed at 10 K. The impact of strain on PL response was revealed by peak energy positions and line width. In addition, valence-band splitting (VBS) and the shift of the heavy-hole were measured. Besides, photoreflectance (PR) at room temperature was useful to establish experimentally the dependence of VBS and band energy shifts (E_0 and E_0 + ?_0) on elastic strain due to lattice mismatches. Other parameters such as the internal electric-field and the electro-optical energy were determined from Franz-Keldysh oscillations analysis. Good correlation between the results obtained from all investigated techniques and theoretical predictions was confirmed.