AVS 50th International Symposium
    Nanometer Structures Tuesday Sessions
       Session NS-TuM

Paper NS-TuM3
Structure, Defect and Cathodoluminescence Studies of GaN Nanorods and Nanowires

Tuesday, November 4, 2003, 9:00 am, Room 308

Session: Nanowires
Presenter: L.C. Chen, National Taiwan University
Authors: L.C. Chen, National Taiwan University
C.S. Shen, National Taiwan University
S.C. Shi, National Taiwan University
S. Dhara, Academia Sinica, Taiwan
C.T. Wu, Academia Sinica, Taiwan
K.H. Chen, Academia Sinica, Taiwan
C.W. Hsu, National Taiwan Normal University
C.C. Chen, National Taiwan Normal University
Correspondent: Click to Email
Single-crystalline GaN and related 1D nanostructures, specifically, binary InN, AlN along with their ternary In@sub 1-x@Ga@sub x@N and In@sub 1-x@Al@sub x@N counterparts have been successfully grown by catalytic chemical vapor deposition. Their structure and optical properties are investigated by scanning and transmission electron microscopy, Raman, photoluminescence (PL) as well as cathodoluminescence (CL) techniques. Diameter and position selective growth of these 1D nitride nanostructures has been demonstrated by pre-treatment of the substrate surface with size-controlled catalyst. Oriented growth of the nanorods was also obtained under hetera- or homo-epitaxial conditions. While PL measurements usually give spectral data from numerous nanowires and nanorods with a broad distribution of diameter, the CL measurements (from room temperature down to 4 K) can easily be performed on single nanowire or nanorod. A higher CL peak position of individual GaN nanorod than that of bulk GaN film was observed, indicating the presence of strain in the pristine nanorod, which is also confirmed by X-ray diffraction analyses. In addition, a blue shift of CL peak position with decreasing the diameter of GaN nanorod was noticed. However, the magnitude of the peak shift is much more pronounced than that estimated from quantum confinement. Finally, Ga@super +@ ions implantation of these GaN 1D nanostructures has been studied using 50-keV Ga@super +@ focused ion beam. Phase transformation and defect structure evolution as a function of irradiated ion-beam fluence is also investigated by electron-microscopy-based techniques.