Bottom-up approach for stress transfer to CNTs

Friday, October 19, 2018

Researchers from the CEMES-CNRS and the University of Crete (Greece) propose a new bottom-up method for the stress transfer to carbon nanotubes over large surfaces allowing to manipulate in an appropriate way their band structure and consequently to develop modern and efficient HF semiconductor devices. The method is potentially compatible with high end technological application.

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The extreme mobility of charge carriers, ballistic transport and compatibility with CMOSs ??(complementary metal-oxide-semiconductor) makes carbon nanotubes (CNTs) promising candidates for replacing the silicon channel in HF transistors. However, metallic CNTs are zero bandgap materials that limits their use in HF nanoelectronics. Early theoretical and experimental work predicted and confirmed the band gap opening in deformed metallic CNTs. The development of a controlled and repetitive deformation of the CNTs would make it possible to appropriately manipulate their band structure and consequently to develop modern and efficient HF semiconductor devices. However, there is an essential breach between existing laboratory scale methods applied for deformation of low-dimensional materials and the needs of large-scale production. In this work, we have proposed a bottom-up method for the transfer of stress to these materials, which is potentially compatible with high end technological application. The CNTs deposited and nanostructured on the flat surface of an oxidized silicon wafer, which has been preliminary implanted with H+ and He+ ions, are anisotropically deformed over blisters produced after thermal annealing [1]. The blisters appeared beneath the surface after the thermally activated formation of micro-cracks filled with gas and elastically relaxed through the deformation of the surface. The deformation of the CNTs is manipulated at the local scale (<1μm) by modifying the height/radius ratio of the blisters imposed by the implantation and annealing conditions [2-4]. Using resonant Raman spectroscopy, we demonstrate that the CNTs attached by contacts at their ends deform over blisters up to a strain of 0.15 ± 0.03%, which is in good agreement with the value calculated from the blisters' dimensions. This approach can become a powerful tool for the elaboration of other 1D and 2D materials with predetermined optical or electrical properties. These results have been published in Nanotechnology [1].

References

[1] A bottom-up approach for controlled deformation of carbon nanotubes through blistering of supporting substrate surface,
V. S. Prudkovskiy, F. Iacovella, K. P. Katin, M. M. Maslov, and N. Cherkashin,
Nanotechnology 29 (36), 365304 (2018).
https://doi.org/10.1088/1361-6528/aacc5d

[2] “Impact of He and H relative depth distributions on the result of sequential He+ and H+ ion implantation and annealing in silicon
N. Cherkashin, N. Daghbouj, G. Seine, A. Claverie,
J. of Appl. Phys. 123 (16), 161556 (2018).

[3] “Effect of the order of He+ and H+ ion co-implantation on damage generation and thermal evolution of complexes, platelets, and blisters in silicon”,
N. Daghbouj, N. Cherkashin, F.-X. Darras, V. Paillard, M. Fnaiech, A. Claverie,
J. of Appl. Phys. 119 (13), 135308 (2016).

[4] “Cracks and blisters formed close to a silicon wafer surface by He-H co-implantation at low energy”,
N. Cherkashin, N. Daghbouj, F.-X. Darras, M. Fnaiech, A. Claverie,
J. of Appl. Phys. 118, 245301 (2015).

Contact

Dr. Nikolay Cherkashin, CEMES (CNRS)
nikolay.cherkashin at cemes.fr

 

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