UBC Theses and Dissertations
Faraday effect studies of CdS and CdIn2S4 Gaglardi, Kenneth Joseph
The Faraday effect is used to study the properties of donor and conduction electrons in CdS and Cdln₂S₄. The experiments on CdS give additional information to that obtained from previous ESR measurements which showed possible 'impurity banding* at concentrations much less than 2x10¹⁸/cc. The electrons are shown to behave at high frequencies as if they were free and at low frequencies as if they were localized. The concentration dependence of the conduction band electronic effective mass was measured using the free carrier Faraday effect and found to be constant to within the experimental error of 7% over the concentration range 3x10¹⁷to 7.6x10¹⁸/cc. The uncertainty is much less than presently reported in the literature but too large to verify the increase of 2% over the concentration range predicted by a k.p calculation. A larger Faraday rotation than anticipated was observed at 2°K and an explanation is presented in terms of additional electric-dipole magneto-absorption entering through the spin-orbit interaction. This is interpreted as the observation of the so-called 'combined resonance' effect in CdS. The conduction band electronic effective mass of Cdln₂S₄ was determined from Faraday effect measurements and found to be m*/m₀=0.17± .02. To obtain this value it was necessary to measure the index of refraction in the near infrared spectral region between 0.6 and 1.6µ. A value of 2.57 was found at 1.6µ.
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