Studies on Dispersion Behavior of Phonons in AlN/GaN/AlN Heterostructure

Abstract

Dispersion relation of a material is of general importance in predicting its electronic structure, thermal behavior and optical properties. It becomes quite important in low dimension systems such as nanostructure (quantum dot, nanowire and thin film) and heterostructure. Because, in the low dimensional systems, understanding of propagation of phonon is of quite importance as it is responsible for change in various physical properties. Therefore reduction of problem to elastic continuum model and MATLAB programming has carried out for GaN free standing nanostructure and AlN/GaN/AlN heterostructure. The dispersion behavior for the free standing GaN has been found to be anomalous as compared to its bulk counterpart. The difference in the dispersion of GaN free standing nanostructure and AlN/GaN/AlN heterostructure has also been noticed. The difference might be coming due to changed nature of phonon waves at the interfaces. The variation of group velocity with propagation constant has also been studied. Again the different behavior of bulk sample, free standing nanostructure and nanostructure has been found.