Fabrication of CuInSe2 and Cu(In,Ga)Se2 Absorber Layers\ud by Pulse- and Pulse-reverse Electrochemical Techniques\ud for Solar Photovoltaic Applications

摘要

Global energy crisis is one of the major concerns of the humankind due to the limited\udavailability of fossil fuels which accomplish dominant portion of present days‟ energy.\udHence, the need to develop renewable energy resources has come to the forefront of\uddiscussion. Solar photovoltaic is one of the major alternatives for future energy harvesting\udsystem; however, the utility of this emerging technology depends on the efficiency of the\udsolar cell and viable techniques to commercialize it. Though silicon based photovoltaic\udtechnology is the most dominant till date but expensive manufacturing techniques pertaining\udto it is a major concern. In this context, chalcopyrite Cu(In,Ga)Se2 (CIGS) thin-film\udtechnology has already witnessed high conversion efficiencies due to its suitable bandgap (≈\ud1.20 eV) and large optical absorption coefficient (≈ 105 cm-1). The highly efficient CIGS\uddevices are often fabricated using expensive vacuum based technologies; however, efforts to\udseek an economical and scalable method for the production of stoichiometric CIGS thinfilms\udhave been ongoing to realize the commercialization of these devices. In pursuit of this,\udelectrodeposition has been demonstrated to produce CIGS devices with high efficiencies\udand it is easily amenable for achieving large area films of high quality with efficient\udmaterial utilization and high deposition rate. The use of multi-steps, complexing agents,\udorganic additives during the deposition using a three-electrode system followed by a\udconventional selenization step have often been employed to achieve chalcopyrite compact\udCIGS which make the process more complex and expensive.