AWARDEE OF PHYSICS PRIZE
Xie Sishen (S.S.Xie),physicist, was born on February 18,1942 in Qingdao, Shangdong Province. Graduated from the Department of Physics of Peking University in 1965, Xie Sishen got his Ph.D. degree in 1983 from the institute of physics , Chinese Academy of Sciences. During the period of 1984-1986, he had been the post-doctoral research fellow in the department of electrical engineering and computer science, Colorado University. He is now a professor and the director of Vacuum Physics Open Laboratory of Chinese Academy of Sciences.
The research interests of Prof. Xie focused in many fields of Condensed Matter Physics, including phase diagrams, structures and properties in the rare earth alloys; synthesis, phase relationship, structural determination and property of High Tc superconductors; nano-scale materials, especially, carbon nanotube and other one-dimensional materials. He is the author and/or coauthor of 140 papers published on the academic journals. He got the first class prize of Chinese National Nature Awards for the discovery of High Tc superconductors at Nitrogen temperature in 1989, and the third class prize of Chinese National Nature Awards for the research on the synthesis, phase relationship and structure determination of High Tc superconductors in 1991.
The studies on the control growth of multi-walled carbon nanotubes and their physical properties are summarized:
1. A large amount of well aligned carbon nanotubes were synthesized using porous substrate containing the catalytic nanoparticles in the pores. The main results are to create the isolated and parallel carbon nanotubes with uniform diameter( 20nm) and spacing (100nm)between tubes. Thus, the control growth on the diameter and orientation of tubes was achieved. This is the first and important step on the study of the growth mechanism and their application of tubes. This invention was granted as Chinese invention patent. Many authors cited our paper and the total citation is 134.
2. Very long carbon nanotubes array was achieved by improving the substrate and growth techno-logy. The length of isolated and parallel tubes is about 2-3mm, and their diameter is uniform (20nm) with very few impurity. Using this long tube array many properties can be measured, for example thermal and mechanical properties. The long tubes might be used as reinforced materials in some composites.
3. The narrowest tube with diameter 0.5nm was obtained using a modified arc discharging .The result is close to the theoretical limit of tube and is also a new approach to control the structure of tubes in the growth .
4. Mechanical properties of carbon nanotubes, such as Young's modulus and tensile strength, were investigated using either a long tubes array or individual tube. The Young's modulus and tensile strength of tubes obtained are less than the prediction of the theory, which can be attributed to the defect and slide between layers of multi-walled tubes. Thermal conductivity and thermal electric power measurement was achieved first , and give the useful information which is important for the devices.