The feat was realized by embedded a single carbon nanotube, 1nm in diameter in a thin layer of zirconium dioxide (ZrO 2) under atomically thin sheets of molybdenum disulphide (MoS 2), about 0.65 nanometers thick.
Only a proof of concept, the prototyped nanotransistor exhibited a switching behaviour and proves the 5nm barrier can be broken for gates. The researchers have yet to develop self-aligned fabrication schemes to reduce parasitic resistances in the device and open the way to scalable on-chip circuit engineering.
Moving to MoS 2 as a transistor material for the channel instead of doped silicon, the researchers circumvented the tunnelling effects that would typically kick in when designing sub-5nm gate barriers. Electrons flowing through MoS2 are heavier, they explain, which allows smaller gates to control their flow. The work at Berkeley Lab was primarily funded by the Department of Energy’s Basic Energy Sciences program.
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Access the paper at https://science.sciencemag.org/content/354/6308/99