Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230029, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Lab, Beijing 100039, Peoples R China
We have obtained the photoelectron diffraction curves from (10 (1) over bar0) and (11 (2) over bar0) crystal planes on GaN (0001) surface by using a polar scan mode of x-ray photoelectron diffraction (XPD). On the basis of principle of "forward focusing" of XPD, we have determined that its polarity is Ga termination. The polarity of GaN (0001) surface is also studied by using, energy dependence photoelectron diffraction called angle-resolved photoemission extended fine structure, as well as the calculation of multiple scattering cluster models, which confirmed that its polarity is Ga termination.