Characterization of Infrared Properties of Layer Semiconductors.
Annual scientific rept. 1 May 84-31 Aug 85,
CALIFORNIA UNIV LOS ANGELES DEPT OF PHYSICS
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Infrared wavelength modulation absorption spectroscopy was employed in the spectral range of 0.3-1.45 eV to study deep level impurities in undoped semi-insulating GaAs grown by the liquid encapsulated Czochralski technique. The sensitivity of the measurements allow us to give credence to changes in absorption at levels of .001cm. The measurements reveal two resonant type peaks with fine structures near 0.39 and 0.40 eV as well as plateaus and thresholds at higher energy. The absorption band at 0.37 eV is interpreted as due to the intra center transition between levels of accidental iron impurity. The absorption band near 0.40 eV can be annealed out by heat treatment and is characterize as belonging to a structural multi level defect complex. Photo induced transient spectroscopy technique also reveal out annealable level at 0.42 eV. Raman backscattering was employed to measure the shift in the frequency of unscreened and screened phonon plasma mode in GaAs in a study of the change in the surface depletion layer widths due to various surface treatments. A technique of photo-mixing was employed to measure the drift velocities in the hot carrier small distance regimes in Coallium Arsenide.
- Atomic and Molecular Physics and Spectroscopy
- Solid State Physics