Room-temperature detection of spin accumulation in silicon across Schottky tunnel barriers using a MOSFET structure

TL;DR

This study demonstrates room-temperature spin injection and detection in silicon using a MOSFET structure with a Schottky tunnel barrier, advancing silicon spintronics without insulating barriers.

Contribution

It introduces a novel room-temperature spin injection method in silicon via a MOSFET with a Schottky contact, eliminating the need for insulating tunnel barriers.

Findings

Clear spin-accumulation signals observed at room temperature

Spin signals enhanced by bias current, reduced by gate voltage

Spin diffusion model explains the observed behaviors

Abstract

Using a metal-oxide-semiconductor field effect transistor (MOSFET) structure with a high-quality CoFe/n^+Si contact, we systematically study spin injection and spin accumulation in a nondegenerated Si channel with a doping density of ~ 4.5*10^15cm^-3 at room temperature. By applying the gate voltage (V_G) to the channel, we obtain sufficient bias currents (I_Bias) for creating spin accumulation in the channel and observe clear spin-accumulation signals even at room temperature. Whereas the magnitude of the spin signals is enhanced by increasing I_Bias, it is reduced by increasing V_G interestingly. These features can be understood within the framework of the conventional spin diffusion model. As a result, a room-temperature spin injection technique for the nondegenerated Si channel without using insulating tunnel barriers is established, which indicates a technological progress for Si-based spintronic applications with gate electrodes.