The mechanical oscillatory behaviors of multiwall carbon nanotube oscillators in gaseous environment are investigated using the molecular dynamics method. The effects of ambient gas and temperature on intertube frictional force and oscillation frequency are analyzed. It is found that the intertube frictional force increases with the ambient gas density and temperature. Higher gas density and higher tem- perature cause a more rapid decay in the oscillation amplitude and an increase of the oscillation fre- quency. Compared to the vacuum environmental condition, the collision between gas atoms and the nanotube walls is a main ingredient leading to the increase of the energy dissipation. Gas damping may be the main reason for the failure of carbon nanotube oscillators working in gas environment. The am- bient temperature also has an important effect on oscillations and low temperature is advantageous to sustain oscillations.
The mold fabrication is a critical issue for the development of nanoimprint lithography as an effective low-cost and mass production process.This paper describes the fabrication process developed to fabricate the large area nanoimprint molds on the silicon wafers.The optimization of e-beam exposure dose and pattern design is presented.The overlayer process is developed to improve the field stitching accuracy of e-beam exposure,and around 10 nm field stitching accuracy is obtained.By means of the optimization of the e-beam exposure dose,pattern design and overlayer process,large area nanoimprint molds having dense line structures with around 10 nm field stitching accuracy have been fabricated.The fabricated mold was used to imprint commercial imprinting resist.
CHU JinKui1,2,MENG FanTao1,2,HAN ZhiTao1,2 & GUO Qing1,2 1 Key Laboratory for Micro/Nano Technology and System of Liaoning Province,Dalian University of Technology,Dalian 116024,China
