Size dependence of the electronic structures and electron-phonon coupling in ZnO quantum dots

作者：Ray, S C; Low, Y; Tsai, H M; Pao, C W; Chiou, J W; Yang, S C; Chien, F Z; Pong, W F^*; Tsai, M H; Lin, K F; Cheng, H M; Hsieh, W F; Lee, J F

来源：Applied Physics Letters, 2007, 91(26): 262101.

DOI：10.1063/1.2824396

The electronic structures and optical properties of various sizes of ZnO quantum dots (QDs) were studied using x-ray absorption, photoluminescence, and Raman spectroscopy. The increase in the intensity ratio of the second-order Raman spectra of longitudinal optical mode and its fundamental mode, which is related to the strength of the electron-phonon coupling (EPC), is found to increase with the size of QD. The trend of EPC also correlates with the increase of the intensity ratio of the O 2p(pi) (I-pi) and 2p(sigma) (I-sigma) orbital features in the O K-edge x-ray absorption near-edge structure (XANES) as the size of QD increases. The EPC and XANES results suggest that the crystal orientations of ZnO QDs are approximately aligned with the c axis parallel with the polarization of x-ray photons.

• 出版日期2007-12-24
• 单位中山大学