The nonresonant interband Faraday rotation in silicon single crystals was measured in the spectral region 0.55 to 3.1 eV. A new modulation method is developed for measuring rotations of the plane of polarization of linearly polarized radiation to an accuracy of better than 0.001° in normal cases. The range of measurements was extended up to 2 eV above the indirect energy gap with sample thicknesses between 1 mm and 1 μm, at temperatures between 100 and 350 K, and in a magnetic field of 2 T. The Faraday rotation increases monotonously in the whole range up to a photon energy of 3.1 eV. As the analysis by means of theoretical dispersion functions, of the dispersion relation known as Becquerel equation, and the temperature dependence shows, the interband Faraday rotation in silicon is only associated with direct transitions, the band gap of which should be between 3.2 and 3.4 eV and is not below 3.1 eV.

Superlattices (SL s) composed of thin Si and Ge layers (Si»Ge», Si»Ge9) have been implanted with As, Ge, and Ga ions with doses ranging from 1 X 10" to 1 X 10' ions cm, and thermally annealed at 600 C for 30 min. The disordering and the intermixing of these SL s have been studied by the Ramanscattering technique and model calculations. The damage created by ion implantation has been estimated using TRIM simulations and a model. We found that when a thin symmetric Si»Ge» SL was rendered amorphous by ion implantation at high doses 5 X 10' ions cm, a mixed Sio &Geo 5 material was produced by thermal annealing, but the crystalline structure of the asymmetric Si»Ge9 SL equally disordered and annealed returns to a different SL structure with very little intermixing between the layers. Using a kinetic model, we calculated the interdiffusion coefficients and it was found that the recrystallization of the Ge layer is a fast process but that of the Si one is slow with respect to the time needed for intermixing. As a result, Ge diffuses mainly in disordered Si layers and Si in ordered Ge layers. In order to explain our experimental results, we equate the diffusion of Si into crystalline Ge to that of Ge into amorphous Si to minimize the effect of interlayer stress. Model calculations explain the difference in behavior between the two types of SL's, and are in good agreement with the Raman data.

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The Faraday effect usually is regarded as to be caused by one single pass of the incident wave through the volume of a material. This description neglects the magnetooptical interface effects and the magnetooptical consequences of multiple reflections within the medium. A matrix calculation model is presented for calculating consistentely magnetooptical reflection and transmission spectra. This method yields as well the magnetooptical effects of homogeneous materials as the magnetooptical effects of arbitrary successions of multilayer systems including coherent and incoherent multiple reflections and magnetooptical interface effects. The theorem of magnetooptical reciprocity is discussed and it is shown, that optical inhomogeneous materials generally yield six independent measurable magnetooptical effects. A physical model is constructed which can be used to determine free carrier density profiles of ion implanted and diffused semiconductors nondestructively by utilizing the magnetooptical properties of the free carrier plasma. Generalized dispersion relations which are as well valid between the magnetooptical reflection effects as between the magnetooptical transmission effects are given.