Sub-1K Cold-Electron\nQuantum Well Switching at Room\nTemperature

Quantum states can provide means to systematically manipulate\nthe\ntransport of electrons. Here we present electron transport across\nquasi-bound states of two heterogeneous quantum wells (QWs), where\nthe transport of thermally excited electrons is blocked or enabled\ndepending on the relative positions of the two quasi-bound states,\nwith an abrupt current onset occurring when the two QW states align.\nThe QW switch comprises a source (Cr), QW1 (Cr<sub>2</sub>O<sub>3</sub>), QW2 (SnO<sub><i>x</i></sub>, <i>x</i> <\n2), a tunneling barrier (SiO<sub>2</sub>), and a drain (Si), where\nthe effective electron mass of QW1 (<i>m</i>*<sub>QW1</sub>) is selected to be larger than QW2 (<i>m</i>*<sub>QW2</sub>). The current–voltage (<i>I</i>–<i>V</i>) measurements of the fabricated devices show abrupt current\nonsets, with the current transition occurring within 0.25 mV, corresponding\nto an effective electron temperature of 0.8 K at room temperature.\nSince transistor power consumption is fundamentally tied to effective\nelectron temperature, this sub-1K cold-electron QW switching holds\npromise for highly energy-efficient computing.