Abstract
The photocapacitance of a thin‐film CdZnS/CuInSe2 heterojunction was observed under white light excitation. Capacitance increases were observed that were indicative of minority‐carrier trapping in the junction. Emission spectroscopy indicated that a distribution of traps produce this signal. Analysis of the data indicate trap distributions ranging from 5×1014 cm3 to 1.6×1015 cm3 in the bulk and 3.3×1011 cm2 at the surface. Photovoltaic efficiency was inversely related to the photocapacitance signal. A model relates deep electron interface states to a decrease in open‐circuit voltage.