Microheater Actuators as a Versatile Platform for Strain Engineering in 2D Materials

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 µm/ºC, 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.

Biaxial versus uniaxial strain tuning of single-layer MoS2

“…Although many theoretical works predicted that biaxial strain can tune more effectively the band structure of MoS2 [16][17][18]24,25,29,30,34,44], most of the experimental works only deal with the specific case of uniaxial strain [19,20,22,[26][27][28]33,35,[37][38][39][40][41][45][46][47]49,50]. To date, only a handful of experimental works explored the application of biaxial strain to atomically thin MoS2 using piezoelectric substrates [21], thermal expansion mismatch [31,36,42,43,51], exploiting the presence of naturally occurring bubbles [48,52,53], the creation of artificial blisters [32,54,55] or bubbles [56][57][58], a thin film stressor method [59] or a capillary-pressure-induced nanoindentation method [60]. All these methods present some disadvantages (complexity, cross-talk, etc.)…”

First-Principles Prediction of Two-Dimensional B3C2P3and B2C4P2: Structural Stability, Fundamental Properties, and Renewable Energy Applications

“…Therefore, the band gap size as well as the tunability of the band gap are essential characteristics of photocatalytic materials. , The possibility of controlling the band gap size of 2D B 3 C 2 P 3 and ways for the realization of this process are considered. For that, strain engineering, which is one of the most functional methods for an engineering of band gap of 2D materials, is implemented. Figure a shows the band gap size of 2D B 3 C 2 P 3 as a function of applied axial compressive and tensile strains.…”

Mechanical, Elastic, and Adhesive Properties of Two‐Dimensional Materials: From Straining Techniques to State‐of‐the‐Art Local Probe Measurements

“…As discussed in greater detail in the following Section, these methods mainly rely on pre-stressed [23] or patterned [24][25][26][27][28][29][30] substrates, as well as on local heating protocols. [31] This latter method also allows for the achievement of a dynamic, albeit slow (<3 Hz modulation frequency) control of the obtained lattice deformations. Afterwards, Section 2 moves on to the description of membrane indentation methods, which typically rely on an AFM tip to achieve a controlled, real-time deformation of a suspended 2D membrane.…”