Electronic transistors made of gallium oxide—these components could increase the energy output and improve the design of electric vehicles, solar power, and other forms of renewable energy.
Researchers at the University at Buffalo (UB) have recently made strides in this area, creating a gallium oxide-based, metal-oxide-semiconductor field-effect transistor (MOSFET) totaling 5 micrometers wide (a sheet of paper is 100 micrometers wide).
“To advance these technologies, we need new electrical components with greater and more efficient power-handling capabilities,” says Uttam Singisetti, Ph.D., associate professor of electrical engineering in UB’s School of Engineering and Applied Sciences, and lead author of the study.
“Gallium oxide opens new possibilities that we cannot achieve with existing semiconductors,” Singisetti explains.
Silicon has usually been the semiconducting material of choice, however, it’s now becoming increasingly difficult to maximize its abilities. Thus, scientists are seeking alternatives, such as silicon carbide, gallium nitride, and gallium oxide.
According to the researchers, an important feature to recognize among these options is bandgap, which measures the amount of energy needed for an electron to enter a conducting state. Thinner, lighter systems that can handle more power are made with high-bandgap material. Plus, high-bandgap systems don’t need vast cooling mechanisms since they can operate at higher temperatures.
Silicon, gallium nitride, and silicon carbide offer a bandgap of 1.1 electron volts, 3.3 electron volts, and 2.4 electron volts, respectively. Gallium oxide tops the bandgap chart with 4.8 electron volts.
After choosing gallium oxide, the UB’s transistor excels in another area—breakdown voltage, which is the amount of electricity needed for gallium oxide to transition from an insulator to a conductor. A device offers more power-handling capabilities if it has a higher breakdown voltage.
According to the UB team, the new transistor more than doubles previous gallium oxide semiconductor figures with a 1,850-volt breakdown voltage.
“We’ve been boosting the power-handling capabilities of transistors by adding more silicon. Unfortunately, that adds more weight, which decreases the efficiency of these devices,” says Singisetti. “Gallium oxide may allow us to reach, and eventually exceed, silicon-based devices while using less materials. That could lead to lighter and more fuel-efficient electric vehicles.”
In the meantime, the researchers will further develop the design, specifically attempting to work around the low thermal conductivity of gallium oxide.
Read the article, “1.85 kV Breakdown Voltage in Lateral Field-Plated Ga2O3MOSFETs,” published in IEEE Electron Device Letters, to learn more.
You can watch the transistor reach 1.85 kV in the video below.
