First-principles on Stress Reduction Mechanism of Copper Doped Diamond-like Carbon Films

ZHANG Er-geng, NIU Shuai, CHEN Qiang, PAN Wen-gao, LI Chao-yang

Surface Technology ›› 2020, Vol. 49 ›› Issue (2) : 295-300.

PDF(1146 KB)
PDF(1146 KB)
Surface Technology ›› 2020, Vol. 49 ›› Issue (2) : 295-300. DOI: 10.16490/j.cnki.issn.1001-3660.2020.02.037
Coating Material and Technology

First-principles on Stress Reduction Mechanism of Copper Doped Diamond-like Carbon Films

  • ZHANG Er-geng1, NIU Shuai1, CHEN Qiang1, PAN Wen-gao2, LI Chao-yang2
Author information +
History +

Abstract

The work aims to compare the evolution laws in the properties of diamond-like carbon films doped with different concentrations of copper and analyze the mechanism of the effects of copper doping on the properties of diamond-like carbon films. The initial models of copper-DLC doped with different concentrations of copper (1.56at.%~7.81at.%) and densities of 2.03 g/cm3 and 2.87 g/cm3 were established. The melting annealing and quenching processes were simulated by NVT and NOSE temperature regulation methods, and the geometric model was optimized by conjugate gradient method based on generalized gradient approximation (GGA). The radial distribution functions (RDF), sp3-C content, bulk modulus, bond length and bond angle distribution of the copper-DLC model were calculated by CASTEP and the effects of Cu doping on the stress change of DLC films were also discussed. The proportion of sp3-C hybridization increased with the increase of Cu content. Compared with DLC, the location of the first and second peaks in RDF of Cu-doped DLC shifted significantly. The residual stress in the films decreased first and then increased with the increase of the content of Cu. The residual stress was the smallest when the content of Cu was 1.56at.%(7.2 GPa). With the increase of Cu content, the peak value of the total bond angle distribution decreased, the peak width moved to the small bond angle, and the peak value of the total bond length distribution decreased, resulting in a small and wide peak in the long bond length direction. The weak bond properties of C—Cu and the relaxation of twisted bond angles and bond lengths have significant effects on the reduction of residual compressive stress. At higher concentration of Cu, the proportion of twisted C—C bonds increases, and more twisted C—Cu and Cu—Cu structures are formed, which is the key factor leading to the increase of residual stress.

Key words

Cu-DLC; first principle; stress reduction; radial distribution function; residual stress; bond length; bond angle

Cite this article

Download Citations
ZHANG Er-geng, NIU Shuai, CHEN Qiang, PAN Wen-gao, LI Chao-yang. First-principles on Stress Reduction Mechanism of Copper Doped Diamond-like Carbon Films[J]. Surface Technology. 2020, 49(2): 295-300

Funding

Key Support Plan of Shanghai Science and Technology Committee (170905038000)
PDF(1146 KB)

Accesses

Citation

Detail

Sections
Recommended

/