Microheater actuators as a versatile platform for strain engineering in 2D materials

TL;DR

This paper introduces microheater-based thermal actuators that enable precise biaxial strain engineering in 2D materials, allowing optical property modulation with high spatial stability and dynamic control.

Contribution

The authors develop a novel microfabricated thermal actuator platform for controlled biaxial strain application in 2D materials, demonstrating optical spectrum shifts and potential for optical modulators.

Findings

Maximum biaxial strain of 0.64% achieved

Modulation frequency up to 8 Hz demonstrated

Negligible spatial drift of 0.03 um/deg

Abstract

We present microfabricated thermal actuators to engineer the biaxial strain in two-dimensional (2D) materials. These actuators are based on microheater circuits patterned onto the surface of a polymer with a high thermal expansion coefficient. By running current through the microheater one can vary the temperature of the polymer and induce a controlled biaxial expansion of its surface. This controlled biaxial expansion can be transduced to biaxial strain to 2D materials, placed onto the polymer surface, which in turn induces a shift of the optical spectrum. Our thermal strain actuators can reach a maximum biaxial strain of 0.64 % and they can be modulated at frequencies up to 8 Hz. The compact geometry of these actuators results in a negligible spatial drift of 0.03 um/deg, which facilitates their integration in optical spectroscopy measurements. We illustrate the potential of this strain engineering platform to fabricate a strain-actuated optical modulator with single-layer MoS2.