Nano-Welding of Multi-Walled Carbon Nanotubes on Silicon and Silica Surface by Laser Irradiation.
In this study, a continuous fiber laser (1064 nm wavelength, 30 W/cm²) is used to irradiate multi-walled carbon nanotubes (MWCNTs) on different substrate surfaces. Effects of substrates on nano-welding of MWCNTs are investigated by scanning electron microscope (SEM). For MWCNTs on silica, after 3 s irradiation, nanoscale welding with good quality can be achieved due to breaking C-C bonds and formation of new graphene layers. While welding junctions can be formed until 10 s for the MWCNTs on silicon, the difference of irradiation time to achieve welding is attributed to the difference of thermal conductivity for silica and silicon. As the irradiation time is prolonged up to 12.5 s, most of the MWCNTs are welded to a silicon substrate, which leads to their frameworks of tube walls on the silicon surface. This is because the accumulation of absorbed energy makes the temperature rise. Then chemical reactions among silicon, carbon and nitrogen occur. New chemical bonds of Si-N and Si-C achieve the welding between the MWCNTs and silicon. Vibration modes of Si₃N₄ appear at peaks of 363 cm-1and 663 cm-1. There are vibration modes of SiC at peaks of 618 cm-1, 779 cm-1and 973 cm-1. The experimental observation proves chemical reactions and the formation of Si₃N₄ and SiC by laser irradiation.
Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China. ypyuan@bjut.edu.cn.|Beijing Engineering Research Center of 3D Printing for Digital Medical Health, Beijing University of Technology, Beijing 100124, China. ypyuan@bjut.edu.cn.
Yanping
Y
Yuan
Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China. jimin@bjut.edu.cn.|Beijing Engineering Research Center of 3D Printing for Digital Medical Health, Beijing University of Technology, Beijing 100124, China. jimin@bjut.edu.cn.
Jimin
J
Chen
laser; multi-walled carbon nanotubes; nano-welding