Electrons and holes in Si quantum well: a room-temperature transport and drag resistance study

TL;DR

This study explores electron and hole transport in a 22 nm Si quantum well, revealing how electric field-induced electron-hole bi-layers affect conductance and drag resistance at room temperature.

Contribution

It provides the first detailed measurement of electron-hole drag resistance in a Si quantum well at room temperature, demonstrating tunable bi-layer formation and transport properties.

Findings

Hall mobility shows volume inversion/accumulation signatures.

Electron-hole drag resistance decreases from 860 to 37 Ohms with density variation.

Electric field induces bi-layer formation affecting transport characteristics.

Abstract

We investigate carrier transport in a single 22 nm-thick double-gated Si quantum well device, which has independent contacts to electrons and holes. Conductance, Hall density and Hall mobility are mapped in a broad double-gate voltage window. When the gate voltage asymmetry is not too large only either electrons or holes occupy the Si well and the Hall mobility shows the fingerprints of volume inversion/accumulation. At strongly asymmetric double-gate voltage an electric field induced electron-hole (EH) bi-layer is formed inside the well. The EH drag resistance R_{he} is explored at balanced carrier densities: R_{he} decreases monotonically from 860 to 37 Ohms when the electron and hole density is varied between ~0.4-1.7x10^{16} m^{-2}.