| AVS 55th International Symposium & Exhibition | |
| Energy Science and Technology Focus Topic | Tuesday Sessions |
| Session EN-TuP |
| Session: | Energy Focus Topic Poster Session |
| Presenter: | H.-Y. Na, Chosun University, Korea |
| Authors: | H.-Y. Na, Chosun University, Korea J.-S. Park, Chosun University, Korea P.-J. Ko, Chosun University, Korea N.-H. Kim, Chonnam National University, Korea J.-T. Yang, Gwangju College of Korea Polytechnic V W.-S. Lee, Chosun University, Korea |
| Correspondent: | Click to Email |
CdS is widely used for the window layer material for the various thin film solar cells including CdS/CdTe, CdS/Cu2S, and CdS/CuInSe2 due to its excellent permeability with band gap of 2.42 eV while CdTe is one of the most promising photovoltaic materials with a direct band gap of about 1.45 eV, high optical absorption coefficients, the low cost, high efficiency and stable performance. The surface morphology of window layer materials was well known to affect the performances including the gain in photocurrent by increase of light scattering.1 Therefore the surface morphology of CdS thin film as an window layer must be enhanced by the improved processes. Sputtering method was employed for preparation of CdS thin film, but it showed the rough surface morphology. Chemical mechanical polishing (CMP) processing was firstly proposed for improving the surface morphology of CdS thin film on behalf of the plasma treatment reported in some researches. Removal rate was estimated by the obtained results through the application to Hernandez power law as a generalization version of Preston’s equation for a better description of removal rate. Surface roughness and within-wafer non-uniformity (WIWNU%) of the sputtered CdS thin film was also examined with a change of CMP process parameters including table speed and down force. The optimized process condition was selected considering to both the surface roughness and the hillock-free surface with the good uniformity.
1M. Phyton et al., J. Non-Cryst. Solids 2008.