Calculation of capacitance of self-compensated semiconductors with intercenter hops of one and two electrons (by the example of silicon with radiation defects)

Abstract

Low-frequency electrical capacitance of silicon crystals in the case of hopping migration of both electrons and bipolarons (electron pairs) via the defects of one type, which stabilizes the Fermi level near the midgap, is calculated. The crystals with two-level defects in three charge states (+1, 0, or -1) with a negative correlation energy are considered. It is shown that, as the absolute value of the external potential is increased, the capacitance of silicon containing defects with positive correlation energy increases, while that with defects with negative correlation energy decreases. The expression for the drift and diffusion components of current density for bipolarons hopping from defects with the charge state -1 to defects with the charge state +1 was derived for the first time.