Effect of Electrodeposition Potential on Composition of CuIn1−xGa xSe 2 Absorber Layer for Solar Cell by One-Step Electrodeposition

Abstract EN

CIGS polycrystalline thin films were successfully fabricated by one-step cathodic electrodeposition on Mo-coated glass.

In this study, we applied a galvanometry mode with three-electrode potentiostatic systems to produce a constant concentration electroplating solution, which were composed of CuCl2, InCl3, GaCl3, and SeO2.

Then these as-electrodeposited films were annealed in argon atmosphere and characterized by X-ray diffraction.

The results revealed that annealing treatment significantly improved the crystallinity of electrodeposited films and formed CIGS chalcopyrite structure, but at low applied deposition voltage (−950 mV versus SCE) there appeared second phase.

The cross-section morphology revealed that applied voltage at −1350 mV versus SCE has uniform deposition, and higher applied voltage made grain more unobvious.

The deposition rate and current density are proportional to deposition potential, and hydrogen was generated apparently when applying potential beyond −1750 mV versus SCE.

It was found that the CIGS compound did not match exact stoichiometry of Cu : In : Ga : Se = 1 : x : 1 - x : 2 .

This result suggests the possibility of controlling the property of thin films by varying the applied potential during electrodeposition.