Effect of excitation intensity on fluorescence spectra in ZnO nanostructures and its origin

• 来源期刊: 中国科学G辑(英文版)
• 年，卷（期）: 2009,（1）
• 页码范围: 4-12
• 页数: 9页
• 语种: 英文
• DOI: 10.1007/s11433-009-0024-2

摘要

ZnO nanostructures with three kinds of morphologies, namely, tetrapod-, rod-, and sheet-like shape, are synthesized by chemical vapor deposition, conventional solution-phase, and hydrothermal meth-ods, respectively. The fluorescence measurements display that the spectra of these nanostructures exhibit similar unexpected change laws with the altering excitation intensity. It is observed that when the excitation intensity increases, for the green emission band, the peak position shows a small blue-shift, the width turns broader, and the intensity grows first stronger and then weaker; for the UV emission band, the peak position exhibits a significant red-shift, and the width and intensity have the similar behaviors with those of the green band. Additionally, the relative intensity of green emission to UV emission decreases gradually. It is clarified that the origin of this abnormal phenomenon is as-cribed to the local laser heating effect and the high sensitivity of nanostructures to this heating effect.