Challenging the Electrodeposition of Multinary Semiconductor Compounds: Case of CuInSe_2

摘要

The electrodeposition of multinary compounds is of key importance for future technologies. Cu-In-Se system represents a case example, with a great potential in the field of photovoltaics. At IRDEP we achieved efficiencies up to 11.5% based on electrodeposited Cu-In-Se material. In the present paper, nucleation and growth steps of CuInSe_2 are studied by polarization, impedance spectroscopy and SEM. The bulk composition is measured by x-ray fluorescence. The chemical environment of Cu, Se and In and the surface composition are analysed by XPS. A quasi-instantaneous 3D nucleation is observed. Binary Cu-Se nuclei are first obtained, which induce the incorporation of indium leading to CuInSe_2. With increasing growth, secondary phases and Se(0) are obtained. At the threshold of potential corresponding to indium incorporation, a blocking adsorbate is formed, which is reduced at higher cathodic overvoltage into Cu-In-Se compound. These results are discussed in terms of general behavior of multinary compound deposition.