PHOTOELECTROCHEMICAL DETERMINATION OF MINORITY-CARRIER DIFFUSION LENGTH AND ENERGY-BAND GAP IN HEAVILY-DOPED SEMICONDUCTORS .1. HOLE DIFFUSION TRANSPORT IN DEGENERATE N-CDO

A new approach is suggested for determining parameters of heavily-doped semiconductors from photoelectrochemical (PEC) data. Unlike conventional PEC methods, it allows the evaluation of minority-carrier diffusion length (L) and the energy band gap (E(g)) when the photocurrent across the semiconductor-electrolyte junction is affected by interfacial kinetics. The applicability of this approach is demonstrated for polycrystalline degenerate n-CdO. It has been found that there are three valence-band valleys differing in physical and electrochemical parameters for n-CdO minority carriers. The percolation mechanism of hole diffusion transport is assumed to explain extremely high L values (10(-4)-10(-3)cm) obtained for semimetallic cadmium oxide.