| AVS 55th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Tuesday Sessions |
| Session NS-TuP |
| Session: | Poster Session |
| Presenter: | S.-Y. Kuo, Chang Gung University, Taiwan |
| Authors: | S.-Y. Kuo, Chang Gung University, Taiwan F.-I. Lai, Yuan-Ze University, Taiwan W.-C. Chen, National Applied Research Laboratories, Taiwan C.-N. Hsiao, National Applied Research Laboratories, Taiwan |
| Correspondent: | Click to Email |
The morphological and structural evolution is presented for GaN grown by chemical beam epitaxy on (0001) Al2O3 substrates. Their structural and optical properties are investigated by x-ray diffraction, scanning and transmission electron microscopy, and temperature-dependent photoluminescence measurements. While increasing the growth temperature and the flow rate of radio-frequency nitrogen radical, the three-dimensional growth mode will be enhanced to form the one-dimensional nanostructures. The high density of well-aligned nanorods with a diameter of 30–50 nm formed uniformly over the entire sapphire substrate. The x-ray diffraction patterns and transmission electron microscopic images indicate that the self-assembled GaN nanorods are a pure single crystal and preferentially oriented in the c-axis direction. In addition, the enhanced A1(LO) intensity of micro-Raman spectrum confirms the formation of strain-free GaN nanorods in consistent with XRD and HRTEM results. Particularly, the “S-shape” behavior observed in the temperature-dependent photoluminescence might be ascribed to the fluctuation in crystallographic defects and composition. Neither catalyst nor template is required in our epitaxial system make this technique feasible to develop nanodevices based on strain-free III-nitride nanorods.