Clustering Parameter and Internal Stress in III-V Ternary Alloys

Abstract

An application of laser Raman Spectroscopy to estimate the clustering parameters and internal stress accumulated in each bond in Ga_0.5Al_0.5As, Ga_0.52In_0.48P, Ga_1-x In _x As (0 ≤x ≤0.53), and GaAs_0.7P_0.3 is proposed. The clustering parameters and stress are evaluated from the phonon intensity and the difference between the observed optical phonon frequencies and those calculated in terms of the modified RED model, respectively. The estimated values of the clustering parameter agree fairly well with those obtained from theoretical calculation of the excess free energy of mixing. The bond lengths in Ga_1-x In _x As (0 ≤x ≤0.53) are derived from the stress, and are compared with published data on extended X-ray absorption fine structure.