Cu(In,Ga)Se2 thin film solar cells from a single quaternary target.

• Main Author: Lim, Gerard Joseph Chu Keong.
• Other Authors: Lew Wen Siang
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: http://hdl.handle.net/10356/49478
• Institution: Nanyang Technological University

Research and development on sustainable and renewable energy sources such solar energy have been progressive in a bid to mitigate future energy demand, as well as to counter the steadily exhausting supply of conventional sources of energy such as coal and fuel. With the increase in demand for solar energy and solar cells, photovoltaic power and solar cell fabrication plants have been attempting to meet this growing demand. The use of silicon for such photovoltaic devices, as well as for the larger electronics industry, has driven up the cost of silicon. Such is the motivation for the development of alternative photovoltaic device material. CIGS thin film solar cells have achieved about 20% in laboratory efficiency, and are an attractive thin film solar cell technology. Unlike polycrystalline silicon, the CIGS absorber material has a direct bandgap that is close to the optimal energies for single junction solar cells. Also, as compared to the 170 - 250µm absorber thickness for silicon solar cells, CIGS thin film requires only about 2.5µm of semiconductor material, reducing the cost of production and making the technology less susceptible to commodity pricing of raw material or shortages. In this report, semiconductor and solar cell device physics are discussed, as they are fundamental to the objectives of this project. Literature review for the different materials involved and the fabrication of a CIGS solar cell are covered. Sputter and chemical bath deposition (CBD) methods were employed in the fabrication of CIGS thin film solar cells. Thickness calibration and surface morphology were obtained using atomic force microscopy, while crystal structure was analyzed using X-ray diffraction. The fabricated cells were then characterized via solar measurement to obtain the I-V curve. This report’s emphasis is on the deposition of the absorber layer using a single quaternary CIGS target to obtain the heterostructure of a CIGS solar cell.