Bulg. J. Phys. vol.22 no.3-4 (1995), pp. 030-038



Ionization of Surface Centres as a Method for Studying Their Parameters

I.A. Baev, V.T. Panayotov, V.M. Lilkov
Department of Physics, University of Mining and Geology, 1100 Sofia, Bulgaria
Abstract. A method is described for determination of parameters characterizing surface impurity centers localized in the interface of the Metal-Oxide-Semiconductor structures W-Native oxide-n-InSb, W-Native oxide-p-FeS2 and W-Native oxide-p-PbS. It was established that over certain critical field values impact ionization of surface centers in the interface begins and relaxation current and voltage oscillations rise, current and voltage being different periodical functions of time. The oscillation process is represented as a periodical bending and straightening of band edges in the surface region. Since upon the surface-potential-barrier relaxation, the surface centers are filled and emptied periodically, an experimental study of the recharging process offers an opportunity to determine the density of the surface states, the effective cross section and the charge-carrier-capture time.

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