Electron Transfer at the n-InP poly(pyrrole) Interface

摘要

Measurements of the barrier height by capacitance-voltage techniques and of the equilibrium exchange current density by current-voltage techniques are performed on the rectifying interface between n-InP and poly(pyrrole) (chemically polymerized and characterized by an electrochemical potential of =0.2V vs. SCE). The current-voltage data yielded a quality factor of 1.2 ± 0.1 and an equilibrium exchange current density of (1.2 ± 0.6) × 10~(-9) A cm~(-2). The capacitance-voltage data yielded a barrier height of 0.73 ± 0.02 V and measured dopant densities within 15% of the expected value. These data, taken together, are inconsistent with thermionic emission theories developed to describe inorganic semiconductor ) metal interfaces and often applied to inorganic semiconductor | doped conjugated polymer interfaces. In particular, the ratio of the rate constant for majority carrier electron capture (surface recombination velocity) at the n-InP | poly(pyrrole) interface to that at n-InP | metal interfaces is found to be (6 ± 5) × 10~(-3).