Raman spectroscopy study ofAl0.48In0.52As/InP

We have measured 300-K Raman scattering (RS) from several samples of 〈100〉 ${\mathrm{Al}}_{0.48}$ ${\mathrm{In}}_{0.52}$As/InP grown by molecular-beam epitaxy with substrate temperatures, $T_s$, in the range 495 °C<$T_s$<550 °C. The 4-K photoluminescence (PL) from these samples has also been studied. The details of the longitudinal-optical phonon RS line shape are interpreted in terms of a ‘‘spatial correlation model.’’ At $T_s$=515 °C there is a significant decrease in both RS and PL linewidths indicating that under this growth condition there is a decrease in the alloy potential fluctuations, i.e., a tendency towards ordering. The ‘‘spatial correlation model’’ line-shape analysis is compared with a recently proposed ‘‘discrete-continuum interaction model’’, i.e., Fano-type interaction.