IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Tuesday Sessions
       Session EL-TuP

Paper EL-TuP12
On the Induced Net Charge Density at ICB Deposited MS Interface

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Electronic Materials Poster Session
Presenter: B. Cvikl, J. Stefan Institute, Slovenia
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The origin of the so called excess capacitance of non ideal Schottky junctions has remained unclear for well over the past decade. Recently we have shown,@footnote 1@ utilizing the series of Ag/Si and Pb/Si Schottky junctions deposited by the ionized cluster beam, ICB, method as obtained for different values of external metal ions acceleration voltages, that the origin of the reverse biased excess capacitance is directly related to the occurrence of induced net charge density. This induced net charge density occurs at the, with the penetrating metal ions, enriched Si substrate-Si interface, and its magnitude appears to be a deposition method sensitive. It is the external bias dependence of this induced interfacial net charge, to a very good approximation described by a gaussian curve, which appears to be responsible for the bias dependent excess capacitance in the reverse direction if the junction series resistance is small and in the forward direction if it is not. From the above data extracted analytical expression for the effective density of interface electronic gap states is characterized by numerous sharp spikes the envelope of which exhibits strong, standing wave like oscillations accompanied with nodes. This behavior is strikingly similar to the shape of local density of states of a one dimensional lattice of N identical interacting atoms placed in an external uniform electric field, exhibiting the well known Wannier-Stark ladders.@footnote 2@ In this presentation the possible manifestation of the Wannier-Stark effect in ICB deposited Schottky junctions will be analyzed and the possibility for potential application of the observed effect for certain simple devices will be discussed. @footnote 1@ B. Cvikl and D. Korosak, Vacuum 61 (2001) 355. @footnote 2@ S. G. Davison et al., J. Phys.: Condens. Matter 9 (1997) 6371.