Degree of ordering in Al0.5In0.5P by Raman scattering
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
55
Journal Issue
8
Pages
732031-732034
Date Issued
1997
Author(s)
Abstract
The effects of spontaneous CuPt-like long-range ordering on the lattice dynamics of Al0.5In0.5P alloys was studied by Raman-scattering experiments. The studied samples with various degree of ordering η were grown by metal-organic chemical vapor deposition at different conditions. Raman-scattering experiments were taken in Z(X,X)Z and Z(Y,Y)Z scattering configurations. We observed that, in Z(Y,Y)Z configuration, the ratio R of the intensity of AlP-like LO phonon mode and the intensity of InP-like LO mode is quite different from that measured in Z(X,X)Z scattering geometry, and it increases with increasing the degree of ordering. Because the anisotropy of the photoluminescence (PL) spectra is very difficult to detect in AlInP alloys due to the nature of indirect band gap, the conventional determination of the order parameter from PL spectra thus cannot be applied. We thus introduce a parameter related to the ratio R to denote the degree of ordering in Al0.5In0.5P alloys. This parameter is very easy to obtain and sensitive to the degree of ordering. Our result therefore suggests that the polarized Raman scattering is a very powerful and nondestructive measurement to determine the degree of ordering in semiconductor alloys.
Type
journal article