Flipping growth orientation of nanographitic struc
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Posted On: 04/10/2017 2:15:56 PM
Flipping growth orientation of nanographitic structures by plasma enhanced chemical vapor deposition
Subrata Ghosh, K. Ganesan, S. R. Polaki, S. Ilango, S. Amirthapandian, S. Dhara, M. Kamruddin, A. K. Tyagi
(Submitted on 7 Apr 2017)
Nanographitic structures (NGSs) with multitude of morphological features are grown on SiO2/Si substrates by electron cyclotron resonance - plasma enhanced chemical vapor deposition (ECR-PECVD). CH4 is used as source gas with Ar and H2 as dilutants. Field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy are used to study the structural and morphological features of the grown films. Herein, we demonstrate, how the morphology can be tuned from planar to vertical structure using single control parameter namely, dilution of CH4 with Ar and/or H2. Our results show that the competitive growth and etching processes dictate the morphology of the NGSs. While Ar-rich composition favors vertically oriented graphene nanosheets, H2-rich composition aids growth of planar films. Raman analysis reveals dilution of CH4 with either Ar or H2 or in combination helps to improve the structural quality of the films. Line shape analysis of Raman 2D band shows nearly symmetric Lorentzian profile which confirms the turbostratic nature of the grown NGSs. Further, this aspect is elucidated by HRTEM studies by observing elliptical diffraction pattern. Based on these experiments, a comprehensive understanding is obtained on the growth and structural properties of NGSs grown over a wide range of feedstock compositions.
https://arxiv.org/abs/1704.02165
Conclusion :
We demonstrate the growth and possibility of tunable morphology of nanographite structure (NGSs) on SiO2 substrates using ECR-PECVD by an appropriate composition of feedstock gases. It is found that the dilution of CH4 with Ar and H2 results in vertical and planar structure respectively and also the intermediate structures are always possible with mixed Ar and H2 dilution. The growth mechanism for the different morphological NGSs is due to the competitive growth and etching processes. The Raman studies reveal that the dilution of CH4 with carrier gases minimizes the defects density. Hence, this study helps to grow NGSs with desired morphology
This manuscript got published in RSC Adv., 2015,5, 91922-91931 web link : pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra20820c
Subrata Ghosh, K. Ganesan, S. R. Polaki, S. Ilango, S. Amirthapandian, S. Dhara, M. Kamruddin, A. K. Tyagi
(Submitted on 7 Apr 2017)
Nanographitic structures (NGSs) with multitude of morphological features are grown on SiO2/Si substrates by electron cyclotron resonance - plasma enhanced chemical vapor deposition (ECR-PECVD). CH4 is used as source gas with Ar and H2 as dilutants. Field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy are used to study the structural and morphological features of the grown films. Herein, we demonstrate, how the morphology can be tuned from planar to vertical structure using single control parameter namely, dilution of CH4 with Ar and/or H2. Our results show that the competitive growth and etching processes dictate the morphology of the NGSs. While Ar-rich composition favors vertically oriented graphene nanosheets, H2-rich composition aids growth of planar films. Raman analysis reveals dilution of CH4 with either Ar or H2 or in combination helps to improve the structural quality of the films. Line shape analysis of Raman 2D band shows nearly symmetric Lorentzian profile which confirms the turbostratic nature of the grown NGSs. Further, this aspect is elucidated by HRTEM studies by observing elliptical diffraction pattern. Based on these experiments, a comprehensive understanding is obtained on the growth and structural properties of NGSs grown over a wide range of feedstock compositions.
https://arxiv.org/abs/1704.02165
Conclusion :
We demonstrate the growth and possibility of tunable morphology of nanographite structure (NGSs) on SiO2 substrates using ECR-PECVD by an appropriate composition of feedstock gases. It is found that the dilution of CH4 with Ar and H2 results in vertical and planar structure respectively and also the intermediate structures are always possible with mixed Ar and H2 dilution. The growth mechanism for the different morphological NGSs is due to the competitive growth and etching processes. The Raman studies reveal that the dilution of CH4 with carrier gases minimizes the defects density. Hence, this study helps to grow NGSs with desired morphology
This manuscript got published in RSC Adv., 2015,5, 91922-91931 web link : pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra20820c
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