New transverse tunneling field-effect transistor

A transverse tunneling field-effect transistor. This is a semiconductor device that can be used to amplify or switch electrical power or signals, operating through a phenomenon known as quantum tunneling. The new transistor, introduced in a paper published in Nature Electronics, was built using a van der Waals heterostructure, a material with atomically thin layers that do not mix with each other, but are instead attached via van der Waals interactions. Tunnel field-effect transistors are an experimental type of semiconductor device that operate via a mechanism known as band-to-band tunneling (BTBT). These transistors have a wide range of applications, for instance, in the development of radiofrequency (RF) oscillators or memory components for electronic devices. In these devices, carriers (i.e., particles carrying an electric charge) typically tunnel through a barrier, heading in the same direction as the total output current. The current in this tunnel contributes directly to the device's overall current.

To operate most effectively, these devices should ideally be built with high-quality interfaces and sharp energy band edges. Two-dimensional van der Waals heterostructures may thus be optimal candidates for their fabrication, as researchers can easily stack different materials on top of each other, resulting in high-quality interfaces and sharp band edges. To enable high tunneling efficiency in semiconductor devices, researchers must be able to tune the density of states with Fermi-level alignment and conserve momentum from the source to end in the momentum space, without involving phonons. The researchers who carried out the recent study featured in Nature Electronics found that using 2-D black phosphorus (BP) allowed them to do both these things.

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