Preferential orientation of diamond formation on TaC: Diamond(111)//TaC(111)

Abstract

Experimental results showed that for the diamond film prepared by hot filament chemical vapor deposition (HFCVD) using Ta filament, TaC existed between diamond and the silicon substrate, and diamond grew directly on TaC, while the inherent mechanism was not clear. Here, a special coherent interface Diamond(111)//TaC(111) is observed using high resolution transmission electron microscopy, and then we explore the effects of the TaC with different lattice planes on the diamond formation by first-principle calculations. The results show that C tends to adsorb on the TaC(111) C-terminated surface. The strong covalent bond between C from diamond and Ta from TaC is formed in the Diamond(111)//TaC(111) interface, while only C–C covalent bonds are formed at the Graphite(002)/TaC(111). This makes diamond thermodynamically more stable than graphite on the TaC surfaces. Our investigations provide critical information to understand the complex diamond formation mechanism, especially with the presence of TaC.

Keywords:

• Diamond film
• HFCVD
• TaC
• Diamond(111)/TaC(111) interface
• Graphite(002)/TaC(111) interface

Authors’ contributions

Shaohua Lu: investigation, data curation, writing—original draft, visualization. Xiongtao Zhang: investigation, data curation, writing the original draft. Yuhao Zheng: investigation, data curation. Meiyan Jiang: formal analysis. Chengke Chen: formal analysis. Xiaojun Hu: funding acquisition, conceptualization, supervision, writing—review & editing.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by Key Project of National Natural Science Foundation of China (Grant No. U1809210) and National Natural Science Foundation of China (Grant Nos. 52102052, 11504325, 52002351, 50972129 and 50602039); International Science and Technology Cooperation Program of China (2014DFR51160); Natural Science Foundation of Zhejiang Province (LQ15A040004, LY18E020013 and LGC21E020001); and Key Research and Development Program of Zhe Jiang Province (2018C04021).