CHANGE OF ELECTRICAL CONDUCTIVITY OF CDS SINGLE CRYSTALS DURING HEAT TREATMENTS IN SULFUR VAPOR BETWEEN 500 AND 700C.
DELAWARE UNIV NEWARK DEPT OF PHYSICS
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The electrical conductivity of CdS single crystals was measured, using a four-electrode method, as a function of the S vapor pressure in the range from 10 to 1000 Torr in a double furnace allowing for independent variation of the crystal temperature and S-vapor pressure. In agreement with earlier measurements, the current was observed to decrease with increasing S-vapor pressure following a power law sigma varies as p exp. -1m. The exponent 1m depends on the crystal temperature and is about 124 for 500C T 520C, 14 for 530C T 630C, and about 112 for 640C T 700C. A simple model using S vacancies, Cd interstitials and Cd vacancies is used to explain the observed behavior. Doubly ionized S vacancies are assumed to be predominant in the lowest temperature range, single ionized Frenkel defects in the intermediate temperature range, and doubly ionized Cd interstitials in the highest temperature range. Author
- Solid State Physics