Affiliation: | 1,4 1 Accelerator Laboratory,School of Physics and Technology,Wuhan University,Wuhan 430072,China 2 Key Laboratory of Beam Technology and Material Modification of Ministry of Education,Beijing Normal University,Beijing,100875,China 3 Quantum-Functional Semiconductor Research Center,Dongguk University,Seoul,100-715,Korea 4 Department of Physics,Three Gorges University,Yichang 443000,China |