UBC Theses and Dissertations
Characterization of GaAs/Ga₁₋ Al As multilayer system by infrared spectroscopy at normal incidence Zeng, An
The infrared reflectance spectra of GaAs/Ga₁₋xAlAs multilayer structures at normal incidence from the far-infrared to the near-infrared have been measured using a Bruker IF 113v spectrometer. The main structure in the spectra are due to the phonon reststrahlen bands, the Fabry-Perot interference and the plasma edge of the free carriers. An optical impedance method was successfully used to calculate the reflectance spectra at normal incidence. Through fitting the spectra, we determined both electrical and structural parameters, which are usually determined by several different methods. These parameters include the carrier concentration n, mobility µ, conductivity σ, Al concentration x, and the thickness di of each layer. The agreement between the theoretical spectra and the experiments is excellent.
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