Characterization of ITO/ZnPc/CHR/In p-n junction-photovoltaic device usingJ-V, C-V and photoaction measurements

The electrical and photovoltaic properties of a newly designed two-layered photocell having the configuration ITO/ZnPc/CHR/In p-n junction were invest igated. The rectification effect observed in the device is due to an energy barrier formed between the CHR and ZnPc layer. The depletion layer charact eristics of the device were investigated by measuring the temperature varia tion of capacitance. These measurements indicate that a depletion layer of width 190 nm as well as potential barrier height of about 0.78 eV, decrease s with temperature. The current-voltage characteristics of the device yield a barrier height of about 0.74 eV formed between ZnPc and CHR. The device showed a response to light over the whole visible region extending from 400 nm to 800 nm. The comparison of photoaction spectra with the absorption sp ectra also indicates the formation of an energy barrier between CHR and ZnP c. The dissociation of excitons induced by the built-in field potential exi sting between the CHR and ZnPc layers is responsible for photogeneration of the carriers. Various photovoltaic parameters were calculated and are disc ussed in detail.