[1] Thin Film Physics Division, Department of Physics (IFM), Linköping University, Linköping,SE-58183, Sweden
[2] Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, Uppsala,SE-75120, Sweden
[3] Materials Research Laboratory, Department of Materials Science, University of Illinois, Urbana,IL,61801, United States
[4] Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei,10607, Taiwan