We have studied Raman scattering from 〈100〉 GaAs samples implanted with 270-keV As+ ions with various fluences up to 3.2×1014 cm−2. In addition to phonon density of states effects, we observe a softening and asymmetric broadening of the allowed LO phonon while the small symmetry forbidden TO phonon remains almost unchanged. The behavior of the LO and TO modes can be explained quantitatively on the basis of a ‘‘spatial correlation’’ model related to q-vector relaxation induced by the damage. Our interpretation is quite general and makes it possible to use Raman spectra to evaluate an average size of undamaged regions in semiconductors.

We have studied Raman scattering from CdTe 〈100〉, 〈110〉, and 〈111〉 surfaces subjected to various surface treatments. Our investigation shows that 0.1% Br/methanol etch or chemomechanical polish leaves a thin residual layer of polycrystalline Te of thickness 10–40 Å (under a tensile stress of about 8 kbar) and that this Te film can be removed by a rinse in a 1 N KOH in methanol solution.

The real and imaginary parts of the refractive index, n(ω) and k(ω), of silicon were measured as a function of photon frequency ω using Fourier transform infrared (FTIR) transmission spectral data. An accurate mechanical measurement of the wafer’s thickness, t, was required, and two FTIR spectra were used: one of high resolution (Δω=0.1to0.5cm−1) yielding a typical channel spectrum (Fabry–Perot fringes) dependent mainly on t and n(ω), and one of low resolution (Δω=4.0cm−1) yielding an absorption spectrum dependent mainly on t and k(ω). A procedure was developed to first get initial estimates for n(ω) for the high-resolution spectrum and then calculate k(ω) from the faster low-resolution spectrum with minimal measurement drift. Then both initial n and final k values were used together as starting point data for a fit to the high-resolution spectrum. A previously derived transmission formula for a convergent incident beam was used for the fit. The accuracy of n(ω) determined using this procedure is mostly dependent upon the measurement error in the sample thickness t and k(ω) is dominated by the accuracy of the absolute transmission values obtained from a sample-in and sample-out methods. Our results are compared with previously published values for n(ω) and k(ω) in the 450–4000-cm−1 spectral region. The reported uncertainty in n(ω) is ±10−4 absolute, a factor of 10 better than published values. The values of n(ω) range from 3.4400 at 4000cm−1 (λ=2.5μm) to 3.4169 at 450cm−1 (λ=22.222μm). The k(ω) values had a standard deviation of ⩽±3% and are in good agreement with previous measurements.

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