Large Photothermal Effect in Sub-40 nm h-BN Nanostructures Patterned Via High-Resolution Ion Beam
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hBN_Small.pdf
Size
2.43 MB
Format
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Checksum (MD5)
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Author(s)
Lopez, Josue Jacob
Kong, Jing
Ambrosio, Antonio
Dai, Siyuan
Huynh, Chuong
Eyhusen, Soeren
Bell, David C.
Lin, Xiao
Rivera, Nicholas H.
Ma, Qiong
Date Issued
April 24, 2018
Journal
Small
Publisher
Wiley
Citation
López, Josué J. et al. “Large Photothermal Effect in Sub-40 Nm h-BN Nanostructures Patterned Via High-Resolution Ion Beam.” Small 14, 22 (April 2018): 1800072 © 2018 Wiley
Version
Author's final manuscript
Abstract
The controlled nanoscale patterning of 2D materials is a promising approach for engineering the optoelectronic, thermal, and mechanical properties of these materials to achieve novel functionalities and devices. Herein, high-resolution patterning of hexagonal boron nitride (h-BN) is demonstrated via both helium and neon ion beams and an optimal dosage range for both ions that serve as a baseline for insulating 2D materials is identified. Through this nanofabrication approach, a grating with a 35 nm pitch, individual structure sizes down to 20 nm, and additional nanostructures created by patterning crystal step edges are demonstrated. Raman spectroscopy is used to study the defects induced by the ion beam patterning and is correlated to scanning probe microscopy. Photothermal and scanning near-field optical microscopy measure the resulting near-field absorption and scattering of the nanostructures. These measurements reveal a large photothermal expansion of nanostructured h-BN that is dependent on the height to width aspect ratio of the nanostructures. This effect is attributed to the large anisotropy of the thermal expansion coefficients of h-BN and the nanostructuring implemented. The photothermal expansion should be present in other van der Waals materials with large anisotropy and can lead to applications such as nanomechanical switches driven by light. Keywords: 2D materials; helium and neon ion beam fabrication; hexagonal boron nitride (h-BN), near-field imaging; photothermal effect
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1002/smll.201800072
