Triet Quang Le

Triet Quang Le

University of New Hampshire

Chemical Engineering


2006

Mentor: Dr. Dale Barkey, UNH Department of Chemical Engineering

The Effect of Electrodeposition Parameters on the Bandgap of Copper-Indium-Gallanium-Diselenide (CIGS)

Solar power is one of the best rising technologies for renewable, efficient, pollutant-free energy. Solar energy can generate electricity, provide hot water, and heat offices, homes, and industries. Photovoltaic solar power is a process where electricity is produced directly from the sun’s energy. The semiconductor films required for solar voltaic cells can be fabricated by electrodeposition. This paper reviews the effect of electrodeposition parameters on the bandgap of semiconductors used in solar panels. One of the fundamental limitations on solar cell efficiency is the bandgap of the semiconductor from which the cell is made. The bandgap is the energy difference between the valence and conduction bands. Semiconductor materials used in thin films include amorphous silicon (a-Si), copper indium deselenide (CIS), and cadmium telluride (CdTe). The thin film that will be investigated in this research is copper indium gallanium diselenide, CuInGaSe2 (CIGS). CIGS is one of the most important materials for polycrystalline thin-film cell structures because the bandgap can be vary over a wide range by modification of the composition. The proposed research will analyze bandgap engineering in electrodeposited CIGS

This experiment will contribute to the fundamental understanding of the effect of electrodeposition parameters on CIGS and the practical application of CIGS material to high performance solar cells. The thin-film device in this experiment will be in the form of n-type (negative) material. In order to achieve the n-type material, a high cathodic potential in the range of 0.9-1.30 V is applied to allow more indium and gallium to be deposited in the thin-film. Photons with less energy than the band gap pass through with no absorption, while photons with energy higher than the band gap are absorbed. The bandgap of electrodeposited CuInGaSe2 layers will be measured as a function of deposition current (amps) and agitation to see how the bandgap can be varied by changing the reaction and mass-transfer rates.

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