Graphene-based electromechanical thermal switches

Abstract

Thermal management is an important challenge in modern electronics, avionics, automotive, and energy storage systems. While passive thermal solutions (like heat sinks or heat spreaders) are often used, actively modulating heat flow (e.g. via thermal switches or diodes) would offer additional degrees of control over the management of thermal transients and system reliability. Here we report the first thermal switch based on flexible, collapsible graphene membranes with low operating voltage (∼2 V) and thermal switching ratio up to ∼1.3. We also employ active-mode scanning thermal microscopy to measure the device behavior and switching in real time. A compact analytical thermal model is developed for the general case of a thermal switch based on a double-clamped suspended membrane, highlighting the thermal and electrical design challenges. System-level modeling demonstrates the thermal trade-offs between modulating temperature swing and average temperature as a function of switching ratio. These graphene-based thermal switches present new opportunities for active control of fast (even nanosecond) thermal transients in densely integrated systems.

High Thermal Conductivity of Submicrometer Aluminum Nitride Thin Films Sputter-Deposited at Low Temperature

“…Heat generation impedes the performance and longevity of nearly all modern electronic devices. − This is especially true in high-density integrated circuits and power or radio-frequency (RF) electronics, , where elevated temperatures reduce transistor performance, increase leakage, and ultimately diminish device lifetimes. , A mere 5 °C increase in temperature above the optimum operating range can halve the lifetime of some devices. , Thermal management could be achieved by actively tuning heat flow and managing thermal transients, e.g. with the use of emerging thermal transistors and diodes. − Passive approaches involve simply using thin films to block or route heat away from hot spots in electronics. Such heat spreaders must have high thermal conductivity, but they must often be electrical insulators to prevent cross-talk between componentsa set of properties that are common to only a few materials, such as aluminum nitride (AlN), boron nitride (BN), and diamond.…”

The numerical study on performance evaluation of a thermal switch capacitor in a magnetocaloric cooling device

“…It affects a wide range of applications from electronics 1 to medicine, 2 where controlled and efficient heat transfer are important for improved device performance. 3 Therefore, in recent years, researchers have begun to look beyond the state of the art, by exploiting different thermal control devices (TCDs), i.e., thermal switches, thermal diodes, thermal regulators, or thermal capacitors. 4 , 5 , 6 These types of device provide passive or active control of the heat in an analogous way to how their electrical counterparts control electric current.…”