Photovoltaic devices fabricated on electrodeposited CuInSe₂ films

Abstract

Using both Al–CuInSe 2 Schottky junctions and CdS–CuInSe 2 heterojunctions fabricated on electrodeposited p-type CuInSe 2 films, we have investigated some properties of CuInSe 2 . From current–voltage and capacitance–voltage measurements carried out on these devices, it was found that the electronic quality of the CuInSe 2 film surface was improved after the deposition of the CdS layer. In addition, it was observed that the electronic properties of the heterojunctions were dependent on the In/Cu ratio in the electrodeposited CuInSe 2 films. Using a film with In/Cu = 1.1, we successfully fabricated a cell with an active-area conversion efficiency of 5.2%. Post-fabrication air heat treatment at 180 °C on the CdS–CuInSe 2 devices was found to result in an increase in the charge-carrier concentration in the electrodeposited CuInSe 2 films.