Crystal Growth Centre, Anna University, Chennai, 600 025, Tamilnadu, India.
ACS Appl Mater Interfaces. 2010 Oct;2(10):2863-9. doi: 10.1021/am100539q.
ZnO nanostructures were deposited on GaN (0001), Al2O3 (0001), and Si (100) substrates using a high-pressure pulsed laser deposition (PLD) method. Vertically aligned hexagonal-pyramidal ZnO nanorods were obtained on the Al2O3 and Si substrates whereas interlinked ZnO nanowalls were obtained on the GaN substrates. A growth mechanism has been proposed for the formation of ZnO nanowalls based on different growth rates of ZnO polar and nonpolar planes. Both ZnO nanorods and nanowalls exhibit a strong E2H vibration mode in the micro-Raman spectra. The corresponding fluorescence spectra of ZnO nanorods and nanowalls showed near band emission at 3.28 eV. The ZnO nanorods grown on the Si substrates exhibited better crystalline and optical properties compared with the ZnO structures grown on the GaN and Al2O3 substrates. The high aspect ratio, good vertical alignment, and better crystallinity of the ZnO nanorods with tapered tips exhibited promising field emission performance with a low turn-on field of 2 V/μm, a high current density of 7.7 mA/cm2, and a large field enhancement factor.
采用高压脉冲激光沉积（PLD）法在 GaN（0001）、Al2O3（0001）和 Si（100）衬底上沉积 ZnO 纳米结构。在 Al2O3 和 Si 衬底上获得了垂直排列的六方金字塔形 ZnO 纳米棒，而在 GaN 衬底上获得了互连的 ZnO 纳米墙。提出了一种基于 ZnO 极性和非极性面不同生长速率的 ZnO 纳米墙生长机制。ZnO 纳米棒和纳米墙在微拉曼光谱中均表现出强烈的 E2H 振动模式。ZnO 纳米棒和纳米墙的相应荧光光谱显示在 3.28 eV 处有近带发射。与在 GaN 和 Al2O3 衬底上生长的 ZnO 结构相比，在 Si 衬底上生长的 ZnO 纳米棒表现出更好的结晶和光学性能。具有锥形尖端的 ZnO 纳米棒具有高纵横比、良好的垂直取向和更好的结晶度，表现出有前途的场发射性能，开启场强为 2 V/μm，电流密度为 7.7 mA/cm2，场增强因子大。
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