Surface treatment of CuInGaSe2 thin films and its effect on the photovoltaic properties of solar cells

Solar cells have been fabricated with partial electrolyte treatments of CuInGaSe2- (CIGS) thin film absorbers in lieu of a CdS layer. Treatment of the absorbers in a Cd or Zn containing solution is shown to produce conditions under which efficient solar cells can be fabricated. A similar effect is also observed in CuInGaSSe2 (CIGSS) graded band gap absorbers. These observations can be explained by the ability of Cd and Zn to produce n-type doping or inversion in the surface region. We also provide a brief review of similar work done elsewhere and identify directions for future investigations. (C) 2003 Elsevier Ltd. All rights reserved.