Defect properties of GaAs by positron annihilation |
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Authors: | Chen Zhiquan Ma Li Li Shiqing Yan Hepin Wang Shaojie |
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Institution: | (1) Department of Physics, Wuhan University, 430072 Wuhan, China |
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Abstract: | Positron lifetime and Doppler Broadening spectra have been measured for three types of GaAs semiconductors. Direct evidence
of native vacancy-type defects is found in the semi-insulating (SI-type) and n-type sample as its average lifetime {ie45-1}
andS-parameter are larger than the bulk value. No positron trapping occurred in p-type GaAs. The lifetime spectrum of n-GaAs has
also been measured as a function of temperature. The increase in average lifetime {ie45-2} from 226 ps to 234 ps at the temperature
range 95–330 K was observed and was explained by the ionization of the vacancy. The slight increase in bulk lifetime {ie45-3}
with the temperature was caused by the lattice expansion and expansion coefficient α=14×10−6K−1 was evaluated.
Chen Zhiquan: born in May 1969, Ph.D. graduate student. Current research interest is in positron annihilation.
Supported by the National Natural Science Foundation of China |
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Keywords: | positron annihilation semiconductors defect |
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