Local Structure Invariant Potential for In_xGa_1-xAs Semiconductor Alloys

Abstract

We model lattice-mismatched group III-V semiconductor InxGa1-xAs alloys with the three-parameter anharmonic Kirkwood-Keating potential, which includes realistic distortion effect by introducing anharmonicity. Although the potential parameters were determined based on optical properties of the binary parent alloys InAs and GaAs, simulated dielectric functions, reflectance, and Raman spectra of alloys agree excellently with experimental data for any arbitrary atomic composition. For a wide range of atomic composition, InAs-and GaAs-bond retain their respective properties of binary parent crystals despite lattice and charge mismatch. It implies that use of the anharmonic Kirkwood-Keating potential may provide an optimal model system to investigate diverse and unique optical properties of quantum dot heterostructures by circumventing potential parameter searches for particular local structures.

Structural and optical study of alternating layers of In and GaAs prepared by magnetron sputtering

“…Raman spectra revealed the following: a) A change in the Raman line shape due to an increase in the penetration depth of each laser line; b) A two-mode behavior, typical of III-V alloys, i.e. independent TO and LO phononic modes associated with GaAs and InAs [34][35][36]. c) All the spectra show a shift of approximately 5 cm −1 towards low frequencies with respect to the vibrational modes of GaAs and InAs in bulk, due to the stresses generated in the interfaces during the preparation of the layers.…”