Thin film solar cells have the potential to be an important contributor to the world energy demand in the 21st century. CuInGaSe2 thin film solar cells have achieved the highest efficiency among all the thin film technologies. A steady progress has been made in the research and development of CuInSe2 based thin film solar cells. However, there are many issues that need to be addressed for the development of CuInSe2 based thin films solar cells. High price of PV modules has been a biggest factor impeding the growth of photovoltaic modules for terrestrial application. This thesis tries to address the effects of sodium on the CIGSe and CIGSeS thin film absorbers. A progressive increase in the grain size and the degree of preferred orientation for (112) was observed with the increase in the amount of sodium available during the absorber growth. The distribution of sulfur was also influenced by the microstructure of the film. The increase in the grain size influenced the diffusion of sulfur in the CIGSeS thin film absorber. Deposition of silicon nitride alkali barrier was successfully completed. A new selenium precursor, dimethyl selenide was successfully used for the preparation of CIGSe and CIGSeS thin film solar cells. Systematic approaches lead to the optimization process parameters for the fabrication of the thin films solar cells. CIGSeS thin film solar cell with a reduced thickness of ~2 μm and an efficiency of 9.95% was prepared on sodalime glass substrate. The research presented here proves the potential of dimethyl selenide as selenium precursor to prepare device quality CIGSe absorber. The process can be further optimized to prepare highly efficient absorbers. Electron backscattered diffraction technique was used for first time to analyze the CIGSeS thin film absorbers. Kikuchi patterns and EBSD maps were obtained on the polished CIGSeS thin film absorbers. Grains with various orientations in the EBSD maps were clearly observed. However, it can also be observed that some pixels have not been indexed by the software. This might be due to the departure of crystalline structure of the film from CuInSe2 or the presence of amorphous phases. Data files for indexing and grain orientation of CIGSeS does not exist. However, with the help of lattice parameters and the position of atoms in the base the data file can be created for CIGSeS material.
Dhere, Neelkanth G.
Doctor of Philosophy (Ph.D.)
College of Engineering and Computer Science
Mechanical, Materials, and Aerospace Engineering
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Hadagali, Vinaykumar, "Study of The Effects of Sodium and Absorber Microstructure for the Development of Cuin1-Xgaxse2-Ysy Thin Film Solar Cell Using an Alternative Selenium Precursor" (2009). Electronic Theses and Dissertations. 6135.