Structural and optical characteristics of InGaP layers grown on GaAs substrates by LPE technique

A discussion of the structural and luminescent characteristics of InGaP films lattice matched to GaAs substrates is given. The films were grown by the liquid phase epitaxy technique using a graphite boat in a conventional horizontal reactor. The crystal structure of the layer was characterized by high-resolution X-ray, TEM and EDXS measurements. In the [2 2 0] dark field image in plane view the structure showed a coarse tweed pattern, with a period of 0.2 μm, oriented along the [1 0 0] and [0 1 0] directions. Photoluminescence (PL) measurements were performed in wide temperature (4–250 K) and exciting power density (four orders of magnitude) ranges for [0 1 1] and [0 1̄ 1] polarizations of the emitted radiation. The measured PL spectra showed the presence of deformation related to lattice mismatch and thermal strain. The difference between the spectral peak positions for different polarizations is attributed to the splitting of the valence-band into a heavy- and light-hole bands due to lattice mismatch strain.