%e report the observation of Raman scattering associated with the vibrational modes in the diluted magnetic semiconductor Znl "Mn, Te. The low-frequency two-phonon density-of-states features in Znl "Mn"Te, similar to those of ZnTe, exhibit composition-dependent Raman shifts. Lawfrequency disorder-induced one-phonon density-of-states features are also present in the Raman spectra for x &0.10. The optical phonons of Znl "Mn"Te exhibit a variation with x that is intermediate between the two-mode and one-mode situations. The optical mades af Znl "Mn"Te are compared with those of Cdl "Mn"Te, the prototype of wide-band-gap diluted magnetic semiconductors. A random-element isodisplacement model is used ta describe the behavior of the optical phanons of both alloy systems.

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Intermixing of AlGaAs-based interfaces is known to be enhanced by capping wafers with a layer of SiO2. Assuming that this enhancement results from the introduction of additional Ga vacancies into the sample, it is possible to obtain the temperature-dependent equilibrium Ga vacancy diffusivity. Experiments are performed whereby SiO2-capped quantum well samples are annealed at temperatures ranging from 800 to 1025 °C. Calculated photoluminescence shifts are compared with the measured spectra, and a relation for the Ga vacancy diffusivity of the form 0.962 exp(−2.72/kBT) cm2/s is obtained. Using this relation, the equilibrium Ga vacancy concentration can be computed via an ensemble Monte Carlo simulation. The resulting expression is 1.25×1031 exp(−3.28/kBT) cm−3.

We report the observation of Raman scattering associated with the magnetic excitations in diluted magnetic semiconductors, Cdl "Mn"Te in particular, in an applied magnetic field. A sharp Raman line due to the spin flip of the 3d electrons of Mn +, corresponding to the b mq --+1 transition, occurs in the paramagnetic phase. Close to band-gap resonance, the 4mq --+1 transition in combination with the zone-center LO phonons as well as the hm& --+2 transition are present. In addition to the internal transitions of Mn +, this resonance suggests a new Raman mechanism involving interband transitions in conjunction with the exchange interaction between band electrons and Mn +. In the magnetically ordered low-temperature phase, the magnon feature splits into two components in the presence of an applied magnetic field. As the temperature is lowered and the crystal becomes magnetically ordered, the Mn + spin flip of the paramagnetic phase evolves into the higher-energy component of the magnon.