Autor: |
Villarreal D; Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA., Sharma J; Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA., Arellano-Jimenez MJ; Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA., Auciello O; Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA.; Materials Science and Engineering and Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA., de Obaldía E; Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA.; Facultad de Ciencias y Tecnología, Universidad Tecnológica de Panamá, Panamá City 0819, Panama.; Centro de Estudios Multidisciplinarios en Ciencias, Ingeniería y Tecnología-AIP (CEMCIT-AIP), Panamá City 0819, Panama. |
Abstrakt: |
This article shows the results of experiments to grow Nitrogen incorporated ultrananocrystalline diamond (N-UNCD) films on commercial natural graphite (NG)/Cu anodes by hot chemical vapor deposition (HFCVD) using a gas mixture of Ar/CH 4 /N 2 /H 2 . The experiments focused on studying the effect of the pressure in the HFCVD chamber, filament-substrate distance, and temperature of the substrate. It was found that a substrate distance of 3.0 cm and a substrate temperature of 575 C were optimal to grow N-UNCD film on the graphite surface as determined by Raman spectroscopy, SEM, and TEM imaging. XPS analysis shows N incorporation through the film. Subsequently, the substrate surface temperature was increased using a heater, while keeping the substrate-filament distance constant at 3.0 cm. In this case, Raman spectra and SEM images of the substrate surface showed a major composition of graphite in the film as the substrate-surface temperature increased. Finally, the process pressure was increased to 10 Torr where it was seen that the growth of N-UNCD film occurred at 2.0 cm at a substrate temperature of 675 C. These results suggest that as the process pressure increases a smaller substrate-filament distance and consequently a higher substrate surface temperature can still enable the N-UNCD film growth by HFCVD. This effect is explained by a mean free path analysis of the main precursors H 2 and CH 3 molecules traveling from the filament to the surface of the substrate The potential impact of the process developed to grow electrically conductive N-UNCD films using the relatively low-cost HFCVD process is that this process can be used to grow N-UNCD films on commercial NG/Cu anodes for Li-ion batteries (LIBs), to enable longer stable capacity energy vs. charge/discharge cycles. |