Laser Diagnostics of Plasma in Synthesis of Graphene-Based Materials

2014 ◽  
Vol 2 (3) ◽  
Author(s):  
Alfredo D. Tuesta ◽  
Aizaz Bhuiyan ◽  
Robert P. Lucht ◽  
Timothy S. Fisher

Rotational temperature profiles of H2 in a microwave plasma chemical vapor deposition (MPCVD) reactor were measured via coherent anti-Stokes Raman scattering (CARS) spectroscopy. The temperature was found to increase with reactor pressure, plasma generator power, and distance from the deposition surface. At 10 Torr, the measured temperature range was approximately 700–1200 K while at 30 Torr it was 1200–2000 K under the conditions studied. The introduction of CH4 and N2 to the plasma increased the rotational temperature consistently. These findings will aid in understanding the function of the chemical composition and reactions in the plasma environment of these reactors which, to date, remains obscure.

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Alfredo D. Tuesta ◽  
Aizaz Bhuiyan ◽  
Robert P. Lucht ◽  
Timothy S. Fisher

In an effort to provide insights into the thermochemical composition of a microwave plasma chemical vapor deposition (MPCVD) reactor, the mole fraction of H2 is measured at various positions in the plasma sheath, at pressures of 10 and 30 Torr, and at plasma powers ranging from 300 to 700 W. A technique is developed by comparing the Q(1)01 transition of experimental and theoretical spectra aided by the Sandia CARSFT fitting routine. Results reveal that the mole fraction of H2 does not vary significantly from its theoretical mixture at the parametric conditions examined. Furthermore, the ν″=1→ν′=2 vibrational hot band was searched, but no transitions were found. An analytical explanation for the increase in the temperature of H2 with the introduction of N2 and CH4 is also presented. Finally, because the mole fraction of H2 does not appear to deviate from the theoretical composition, the rotational and translational modes of H2 are shown to be approximately in equilibrium, and therefore, the rotational temperatures may be used to estimate the translational temperatures of H2.


Shinku ◽  
1997 ◽  
Vol 40 (8) ◽  
pp. 660-663
Author(s):  
Hideo OKAYAMA ◽  
Tsukasa KUBO ◽  
Noritaka MOCHIZUKI ◽  
Akiyoshi NAGATA ◽  
Hiromu ISA

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 888
Author(s):  
Pengfei Zhang ◽  
Weidong Chen ◽  
Longhui Zhang ◽  
Shi He ◽  
Hongxing Wang ◽  
...  

In this paper, we successfully synthesized homoepitaxial diamond with high quality and atomically flat surface by microwave plasma chemical vapor deposition. The sample presents a growth rate of 3 μm/h, the lowest RMS of 0.573 nm, and the narrowest XRD FWHM of 31.32 arcsec. An effect analysis was also applied to discuss the influence of methane concentration on the diamond substrates.


2008 ◽  
Vol 47 (4) ◽  
pp. 3050-3052
Author(s):  
Masataka Moriya ◽  
Yuji Matsumoto ◽  
Yoshinao Mizugaki ◽  
Tadayuki Kobayashi ◽  
Kouichi Usami

2000 ◽  
Vol 9 (7) ◽  
pp. 545-549
Author(s):  
Zhang Yong-ping ◽  
Gu You-song ◽  
Chang Xiang-rong ◽  
Tian Zhong-zhuo ◽  
Shi Dong-xia ◽  
...  

CrystEngComm ◽  
2022 ◽  
Author(s):  
Wei Cao ◽  
Zhibin Ma ◽  
Hongyang Zhao ◽  
Deng Gao ◽  
Qiuming Fu

On a semi-open holder, the homoepitaxial lateral growth of single-crystal diamond (SCD) was carried out via microwave plasma chemical vapor deposition (MPCVD). By tuning and optimizing two different structures of...


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