Capacitor Type Thin-Film Heat Flow Switching Device

TL;DR

This paper presents a capacitor-type heat flow switching device that actively controls electron thermal conductivity via bias voltage, demonstrating a 55% increase in thermal conductivity with potential applications in thermal management.

Contribution

The study introduces a novel capacitor-type device with actively tunable electron thermal conductivity using amorphous Si-Ge-Au layers and bias voltage control.

Findings

55% increase in thermal conductivity observed

Device utilizes amorphous low-thermal-conductivity materials

Thermal properties evaluated at room temperature

Abstract

We developed a capacitor type heat flow switching device, in which electron thermal conductivity of the electrodes is actively controlled through the carrier concentration varied by an applied bias voltage. The devices consist of an amorphous p-type Si-Ge-Au alloy layer, an amorphous SiO$_2$ as the dielectric layer, and a n-type Si substrate. Both amorphous materials are characterized by very low lattice thermal conductivity, less than 1 Wm-1K-1. The Si-Ge-Au amorphous layer with 40 nm in thickness was deposited by means of molecular beam deposition technique on the 100 nm thick SiO$_2$ layer formed at the top surface of Si substrate. Bias voltage-dependent thermal conductivity and heat flow density of the fabricated device were evaluated by a time-domain thermoreflectance method at room temperature. Consequently, we observed a 55 percent increase in thermal conductivity.