Title :
Removal of the surface inversion of CuInSe/sub 2/ absorbers by NH/sub 3,aq./ etching
Author :
Hunger, R. ; Schulmeyer, T. ; Lebedev, M. ; Klein, A. ; Jaegermann, W. ; Kniese, R. ; Powalla, M. ; Sakurai, K. ; Niki, S.
Author_Institution :
Surface Sci. Div., Darmstadt Univ. of Technol., Germany
Abstract :
The surface modifications of CIGS and CIS absorbers induced by air oxidation for 16 h, water rinsing, and diluted, 2.5 M ammonia solution, were investigated by synchrotron-excited photoelectron spectroscopy. The air oxidation leads to the outdiffusion of Na to the absorber surface under the formation of Na/sub 2/CO/sub 3/. The surface Na compounds are completely removed by water exposure. Furthermore, the air oxidation and subsequent water rinsing are accompanied by a reduction of the surface Ga concentration by a factor of 2. Ammonia etching effects the complete removal of surface oxides, a significant increase of the surface [Cu]/[In] ratio, and a removal of the initial surface inversion. These effects point towards a preferential leaching of indium out of the absorber surface.
Keywords :
X-ray photoelectron spectra; copper compounds; etching; gallium compounds; indium compounds; inversion layers; oxidation; solar cells; surface diffusion; ternary semiconductors; 16 h; CuInSe/sub 2/; NH/sub 3,aq./ etching; absorber surface; air oxidation; outdiffusion; preferential leaching; surface inversion; surface modification; synchrotron-excited photoelectron spectroscopy;
Conference_Titel :
Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on
Conference_Location :
Osaka, Japan
Print_ISBN :
4-9901816-0-3
