IITs, Vienna university discover cost-effective method to develop ultrawide bandgap semiconductor

NEW DELHI: Researchers at the Indian Institutes of Technology in Guwahati and Mandi and the Vienna University of Technology have developed a cost-effective method to develop a semiconducting material that can significantly enhance the efficiency of power electronics used in high-power applications such as electric vehicles, high-voltage transmission, traction and industry automation, among others. The team developed an innovative and cost-effective technology to grow gallium oxide -- an ultrawide bandgap semiconducting material -- through a customised low-pressure chemical vapour deposition system.

According to officials, this innovation is expected to be used widely as it makes high-power devices function efficiently even at very high temperatures, such as 200 degrees Celsius. The findings of the study have been published in multiple research papers in the "Journal of IEEE Transactions on Electron Devices" and "Thin Solid Films". Ultra-wide bandgap semiconductor (UWBGS) materials are a subset of wide-bandgap semiconductor (WBGS) materials and are defined as those WBGS materials, including diamond and gallium.

UWBGS materials have the potential to support the realisation of devices with even higher levels of performance than other devices. "Power semiconductor devices are the heart of every power electronic system and function primarily as efficient switches, toggling ON and OFF to condition incoming power from the grid to be used by the end-user. For emerging high-power applications, there is a demand for compound semiconductor materials with an ultra-wide bandgap," said Ankush Bag, an assistant professor in the Department of Electronics and Electrical Engineering and Centre for Nanotechnology at the Indian Institute of Technology (IIT)-Guwahati.

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Bag explained that the power electronic systems play a vital role to manage and control the flow of electricity. These are crucial for converting electrical energy from both renewable, including solar and wind, and non-renewable sources such as thermal power plants, into a form compatible with end-user applications in terms of voltage, current and frequency. However, there will always be some losses incurred when the electrical energy passes through a typical power electronic system.

Researchers globally have been working on improving the efficiency of power electronic systems using materials such as gallium nitride and silicon carbide but these have limitations, especially in terms of cost, for high-power applications. "The main challenge was to make thin and smooth films out of the material. After multiple trials and rigorous study, we optimised the gallium oxide semiconductor and incorporated it with tin to improve and modulate its conductivity.

We have successfully developed a superior quality ultra-wide bandgap compound semiconductors and fabricated two terminal devices," Bag said. "The applications of this technology extend to electric vehicles, high voltage transmission, traction systems and industrial automation. A key challenge of this research was creating a gallium oxide thin film on a sapphire substrate, deviating from the common use of gallium oxide substrates.

This shift enhances cost-effectiveness and thermal performance, addressing issues related to the expense and poor thermal conductivity of gallium oxide substrates," he added. Other members of the research team are Satinder K Sharma and Arnab Mondal from the School of Computing and Electrical Engineering at IIT-Mandi and Manoj K Yadav from the Institute of Sensor and Actuator Systems, TU Wien, Vienna in Austria.