The metastable changes of the trap spectra of CuInSe2-based photovoltaic devices

Abstract

Spectra of hole and electron traps of CuInSe2/CdS/ZnO photovoltaic devices have been investigated using deep-level transient spectroscopy. A decrease of the concentration of shallow electron traps and an increase of the hole trap concentration after an injection of electrons has been observed. The effect is metastable below 200 K. A proposed explanation is based on the idea that both levels belong to the same defect in a different charge state. A resemblance of the phenomena related to that defect and to "dangling bond"-type centers in amorphous semiconductors has been indicated. Some consequences of defect conversion for current transport and performance of photovoltaic devices have been discussed. © 1996 American Institute of Physics.