Sub-1K Cold-Electron Quantum Well Switching at Room Temperature

Quantum states can provide means to systematically manipulate the transport of electrons. Here we present electron transport across quasi-bound states of two heterogeneous quantum wells (QWs), where the transport of thermally excited electrons is blocked or enabled depending on the relative positions of the two quasi-bound states, with an abrupt current onset occurring when the two QW states align. The QW switch comprises a source (Cr), QW1 (Cr₂O₃), QW2 (SnO_x, x < 2), a tunneling barrier (SiO₂), and a drain (Si), where the effective electron mass of QW1 (m*_QW1) is selected to be larger than QW2 (m*_QW2). The current-voltage (I-V) measurements of the fabricated devices show abrupt current onsets, with the current transition occurring within 0.25 mV, corresponding to an effective electron temperature of 0.8 K at room temperature. Since transistor power consumption is fundamentally tied to effective electron temperature, this sub-1K cold-electron QW switching holds promise for highly energy-efficient computing.