Strongly Absorbing Nanoscale Infrared Domains within Strained Bubbles at hBN-Graphene Interfaces.

Area of Science:

• Condensed Matter Physics
• Nanotechnology
• Materials Science

Background:

• Graphene's unique electronic properties make it promising for infrared (IR) nanodevices.
• Nanoscale features, like bubbles in van der Waals heterostructures, can significantly impact optoelectronic performance.
• Bubbles in hexagonal boron nitride (hBN)-encapsulated graphene are known to induce strain, altering material properties.

Purpose of the Study:

• To investigate the nanoscale IR response of graphene encapsulated in hBN with bubble-induced strain.
• To correlate the observed IR absorption patterns with specific strain configurations.
• To explore the potential of strain engineering for developing advanced graphene-based IR nanodevices.

Main Methods:

• Scattering-type scanning near-field optical microscopy (sSNOM) was employed to map the nanoscale IR absorption.
• Confocal Raman microscopy was used to analyze strain distribution.
• Vector decomposition analysis was applied to characterize strain configurations.

Main Results:

• Distinct domains with significantly enhanced IR absorption were observed within individual bubbles.
• The boundaries of these IR domains precisely matched the ridges of the bubbles.
• Bubble shape was found to influence the induced strain, leading to varied bi-axial and uni-axial configurations.

Conclusions:

• The enhanced IR absorption is attributed to nanoscale strain domains localized at bubble ridges.
• Graphene's IR properties can be effectively tuned by bubble-induced strain.
• This research offers a pathway for designing future strain-engineered graphene IR nanodevices.