Analysis of Low Temperature Trapping and Recombination in II-VI Compounds Using Photodielectric Techniques.
TEXAS UNIV AUSTIN ELECTRONICS RESEARCH CENTER
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In II-VI compounds at cryogenic temperatures, the photodielectric PD effect is the result of optically-induced changes in the densities of free and trapped carriers. Changes in both the real and imaginary parts of the complex dielectric constant are observable when the semiconductor is placed in a superconducting microwave cavity and irradiated with light. A change in the real part of the dielectric constant results in a sizeable change in the cavity resonant frequency, while a change in the imaginary part of the dielectric constant produces a change in the microwave power absorbed by the semiconductor. Equations are presented which relate the frequency change and power absorption change to the densities and binding energies of trapped carriers, and to the density of free carriers. The PD technique gives a direct measurement of both the free carrier density and the trapped carrier density. Models involving trapping and recombination centers with selected properties are analyzed to reveal the relations between carrier densities and other physical characteristics of the sample. Author
- Solid State Physics