Best MoS2 transistor performance yet claimed by UCLA team

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Materials such as graphene and molybdenum sulphide are exciting scientists with their potential to revolutionise transistors and circuits.

One of the problems with graphene is the lack of a band gap. However, MoS2 has a band gap that enables it to be used to create atomically thin transistors with high on-off ratios and high voltage gain. A team of researchers at UCLA's California NanoSystems Institute has fabricated field effect transistors made from MoS2 and says they show the best performance to date in such a transistor. Transistor performance is judged such factors as cut off and maximum frequencies. The UCLA transistors are said to exhibit cut off and maximum oscillation frequencies 40 to 50 times better than the frequencies for existing MoS2 transistors. The scientists found that electronic devices such as logic inverters or RF amplifiers can be formed by integrating multiple MoS2 transistors on quartz or flexible plastic substrates with voltage gain in the gigahertz regime. The transistors they produced had a cut-off frequency of up to 42GHz and a maximum oscillation frequency of up to 50GHz. "Besides the significant increases in intrinsic performance of the transistors, the layered semiconductor MoS2 represents a highly flexible atomically thin membrane," said Xiangfeng Duan, an associate professor of chemistry and biochemistry at UCLA. "And it can be used to make flexible or stretchable circuitry that could be of great importance for wearable electronics of all kinds."