tunneltransistorer

A tunneltransistorer, sometimes referred to as a tunnel transistor, is a class of semiconductor devices in which current is controlled by quantum tunneling across a p-n junction or a heterojunction, rather than by thermal diffusion across a barrier. The most widely discussed implementation is the tunnel field-effect transistor (TFET). In a TFET, a gate modulates the alignment of the valence band in the p-type source with the conduction band in the n-type drain, enabling band-to-band tunneling when the device is on. The off-state current is typically very small, and with suitable materials, the subthreshold slope can be steeper than the 60 mV/decade limit of conventional MOSFETs at room temperature, allowing potentially lower supply voltages and reduced power.

Variants include homojunction TFETs, where tunneling occurs across a single material, and heterojunction TFETs (HH-TFETs), which use materials with favorable band offsets to increase tunneling probability and on-current. Two-dimensional materials (such as transition metal dichalcogenides) and III-V semiconductors (InAs, GaSb, Ge) have been explored to improve performance. Device design also considers doping profiles, channel length, and interface quality, all of which influence tunneling efficiency and variability.

Applications are mainly in low-power electronics, including ultra-low-power logic, sensors, and neuromorphic systems. Compared with conventional MOSFETs, tunnel transistors promise lower switching energy but face challenges in achieving high on-state current, device-to-device variability, and manufacturing scalability for mainstream use. The concept traces to observations of tunneling diodes and has evolved into active research areas in nanoelectronics.