Physical Properties of Zn1-xCdxSe epifilms
Date Issued
2004
Date
2004
Author(s)
Chang, Jui-Tsung
Abstract
Abstract
Dielectric and conductivity properties of Zn1-xCdxSe epifilms were studied as a function of temperature from 200 K to 460 K and frequency from 20 to 1M Hz. A Debye-like relaxation in the dielectric response has been observed, which is explained in terms of the presence of charge redistribution due to electron hopping among defects. The frequency dependence of dielectric relaxation is analyzed by the Cole-Cole function and Fuoss-Kirwood equation. The activation energy of dielectric relaxation is estimated to be 0.65 eV, which is in good agreement with the values obtained from dc conductivity as well as capacitance measurements. It is found that the activation energy decreases with increasing Cd content and this behavior is interpreted in terms of the four-center model, in which the number of Cd atoms appearing in the nearest-neighbor sites of a defect can have four possible configurations. In addition, we demonstrate that the transport mechanism of the carrier conduction in Zn1-xCdxSe epilayers can be well described by the correlated barrier hopping model.
We also report on the vibrational properties of Zn1-xCdxSe determined by Raman scattering measurements. We found that Zn1-xCdxSe exhibits single mode behavior. The broadening in linewidth and asymmetry can be interpreted in terms of the spatial correlation (SC) model.
Subjects
晶薄膜物理
硒化鋅鎘磊
Zn1-xCdxSe
epifilms
Type
thesis
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