Electrodeposition of High-Purity Indium Thin Films and Its Application to Indium Phosphide Solar Cells

We report on advances in the electrochemical deposition of indium (In) on molybdenum foil that enables deposition of electronic-grade purity, continuous films with thickness in the micron range. The desired In film morphology is obtained from an InCl3 aqueous bath by using a high current density of 250 mA/cm2 and a low deposition-bath temperature of −5°C to increase the nucleation density of In islands until a continuous film is obtained. As an example application, the electrodeposited In films are phosphorized via the thin-film vapor-liquid-solid growth method. The resulting poly-crystalline InP films display excellent optoelectronic quality, comparable to single crystalline InP wafers, thus demonstrating the versatility of the developed electrochemical deposition procedure.