Effect of clusters on long-wavelength optical phonons in Ga1−xInxAs

Abstract

The phonon spectra of Ga1−xInxAs have been studied by measuring the infrared reflectivity at near-normal incidence in the 180 ∼400-cm−1 frequency range. Only one reststrahlen band corresponding to the GaAs-like mode was observed for x≲0.2, and two bands were observed for the remaining composition. The data were analyzed by using the Kramers-Kronig relationship and the dependence of the mode frequencies on alloy composition was interpreted on the basis of the modified cluster model including the effect of clusters. The fact that the calculated oscillator strength for the InAs-like mode is substantially zero in the composition range x≲0.2 explains the reason why phonons of the InAs-like mode are not detected experimentally for x≲0.2. The clustering parameter representing the effect of clusters is determined by fitting the measured mode frequencies to the calculated compositional dependence and takes the maximum value near the midrange of alloy composition.

Modified LPE technique growth and properties of long wavelength InAs0.05Sb0.95 thick film

“…Other ternary alloys, such as AlGaAs, GaAsP and GaPSb [19], show "two-mode" behavior, where two sets of optical phonons are observed over the entire range of alloy composition. The optical phonons of ternary compound InAs x Sb 1−x show a one + two-mode behavior, similar to the GaInAs and GaInSb systems [20]. InAs 1−x Sb x alloy shows a one-mode behavior for the optical phonons in the composition range 0 < x < 0.6 and two-mode behavior for large value of x (x > 0.6) [21].…”

“…InSb and InAsSb have been amply probed by Raman methods [17][18][19][20][21]. Here we show the Raman scattering data of InAs 0.05 Sb 0.95 film with high Sb composition and with thickness up to 120 m. Fig.…”

LPE growth and characterization of mid-infrared InAs0.85Sb0.15 film on InAs substrate

“…The optical phonons of InAs 1 À x Sb x are described as one þ two mode [9], similar to GaInAs [30] and GaInSb [31]. One-mode behavior of the optical phonons for 0 rx r0.6 and two-mode behavior for x 40.6 have been reported [9].…”

Temperature dependence of the Raman spectrum ofAlxGa1−xAsternary alloys

“…Also, the anharmonicity was found to vary with the composition in In 1Ϫx Ga x P. 19 Brafman and Manor 20 observed differences between the effects due to alloying and those produced by ion implantation. Also, the relaxation of the momentum conservation rule, which is not considered in ideal random element isodisplacement ͑REI͒ models 21 and residual stresses can contribute to the peak broadening. It follows that the linewidth has to be studied with extreme caution in order to obtain reliable anharmonic constants and temperature coefficients, d⌫/dT.…”