FIZIKA A 4 (1995) 2, 403-412

size 210 kB


Faculty of Civil Engineering, University of Maribor, and "Jozef Stefan'' Institute, University of Ljubljana, Ljubljana, Slovenia

Received 7 April 1995

Temperature dependence of the effective Schottky barrier heights, fb and the relevant ideality factors, n, deduced from the I-V measurements of the ionized cluster beam, deposited Ag/n-Si(111) structures as a function of the ionized silver atoms acceleration voltage, Ua, were investigated. The observed large differences in the diode saturated reverse current as a function of Ua are interpreted on the basis of the thermionic field emission theory of major charge carrier transport. It is, however, established that the theory can not satisfactory predict our I-V temperature dependent measurements. The qualitative interpretation of measurements is presented, which is based on the proposed conjectured charge carriers energy band diagram. A hypothesis is forwarded that, in addition to the regular Ag/Si Schottky potential barrier, another potential barrier appears at a presumably assumed abrupt interface within the Si wafer, which divides the Ag+ enriched region from the regular n-doped Si depletion region. This barrier affects considerably the shapes of valence and conducting semiconductor energy bands, which may undergo a continuous displacement. The magnitude of the band shift is expected to be an increasing function of the silver dopants density and of their penetration lengths. It is proposed that for Ua ¹ 0, the charge carrier transport is in ICB deposited structures, governed by the regular thermionic field emission of electrons tunnelling through the metal semiconductor barrier, enhanced by the simultaneous charge carriers diffusion arising on account of the multiple-level recombination processes. This current is, presumably, taking place in the vicinity of the above described additional interface, which likely constitutes a strong asymmetrical p-n junction.

UDC 538.93
PACS 73.30.+y, 73.20.At 
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