Electric field of a buried interfacial region measured by positron-lifetime spectroscopy |
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Authors: | YF Shek CC Ling CD Beling S Fung |
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Institution: | (1) Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China, CN |
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Abstract: | Positrons from a radioactive source are implanted into a reverse-biased metal–semiconductor contact and are drifted back towards
the contact by the internal electric field where they trap into voids and annihilate. The electric field dependent interface
annihilation fraction is monitored by way of the intensity of the long (∼400–500 ps) void lifetime component using positron-lifetime
spectroscopy. Unlike previous analyses of such systems a numerical model involving positron drift, annihilation and trapping
into the interfacial state has been constructed to describe the positron dynamics in the presence of the non-uniform junction
electric field. The use of the positron-lifetime technique in probing the internal electric field at buried contacts is thus
demonstrated. Results obtained using the numerical method for the Au, Al and Ni/Semi-Insulating (SI)-GaAs contact systems
are found to be consistent with the findings of previous studies on the Au/SI-GaAs system.
Received: 29 November 2000 / Accepted: 26 February 2001 / Published online: 25 July 2001 |
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Keywords: | PACS: 78 70 Bj 73 30+y 73 40 -c |
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