Researchers at IIT Mandi have developed high-quality, uniform nickel oxide thin films on a silicon substrate using an aerosol-assisted chemical vapor deposition technique using nickel nitrate as a precursor material.
Highly selective contacts are the key to achieving high efficiency in thin film solar cells. These contacts allow one type of carrier (holes) to conduct and other types (electrons) to be blocked.
Nickel oxide (NiO) is an optimal material for hole-selective contacts and is widely used in several photovoltaic technologies. Nickel oxide films with a thickness of the order of nanometers (a hundred thousand times smaller than the width of a single hair) must be produced for use in advanced architectural silicon solar cells.
However, the current development of nanometric thin nickel oxide films by sputtering is very expensive because the equipment used for its production must be imported. The precursor components used in the development of these films, such as nickel acetylacetonate, are also very expensive. The price of this technology limits its possibilities of use.
Researchers at the Indian Institute of Technology Mandi (IIT Mandi) have developed a low-cost process to produce ultra-thin metal oxide films from cheaper starting materials. Specifically, they used an aerosol-assisted chemical vapor deposition technique to deposit a nickel oxide thin film on a silicon substrate.
“Aerosol-assisted chemical vapor deposition technology can produce high-quality, uniform thin films on various surfaces, including silicon, by delivering a vapor-phase precursor in the form of an aerosol,” said lead researcher Kunal Ghosh. “Aerosol enables the deposition of a wide range of oxide-based materials with high precision, making it a versatile and cost-effective method for various materials science and engineering applications:”
The team used nickel nitrate hexahydrate as the nickel salt and the deposition was carried out at 550 C for 15 minutes to produce nickel oxide films about 15 nanometers thick. They analyzed the morphology and composition of nickel oxide films prepared using different characterization techniques.
The project is still in the early stages. However, the technology has the potential to be adopted by industry. This research enhances the manufacturing process of advanced architecture silicon photovoltaic devices, reducing the cost and complexity of commercial technologies.
“Our research shows that it is possible to develop a cost-effective and scalable process to fabricate metal oxide layers for solar cells,” Ghosh said. “This new method has the potential to revolutionize the solar industry by reducing the cost and complexity of current production techniques. Also, since the entire process, including the equipment, is developed in-house, the IP produced will contribute to India’s self-sufficiency in advanced architectural silicon solar cells.”
