STRAIN AND ALLOYING EFFECTS ON THE ELECTRONIC AND VIBRATIONAL PROPERTIES OF INYAL1-YAS ON INP

Photoluminescence and Raman measurements have been carried out as a function of In content (y) in relaxed and strained InyAl 1-yAs alloys grown by molecular-beam epitaxy on InP. From the analysis of photoluminescence data near the lattice matched condition a reliable energy-gap dependence on In content for the strained material has been derived. From this the Bir-Pinkus electronic deformation potentials at the lattice matched condition have been determined. The Raman results for the relaxed material have been interpreted in the framework of the modified random element isodisplacement theory, yielding the localized Al mode in InAs, the gap In mode in AlAs, and quadratic dependences versus y for the different optical-phonon frequencies (AlAs-like and InAs-like). Optical-phonon deformation potentials have been calculated within ab initio theory for AlAs and successfully used to fit the AlAs-like phonon frequencies in strained InyAl 1-yAs. Some problems have been found in interpreting the InAs-like strained phonon frequencies. © 1995 American Institute of Physics.