真空下成長氧化鋅/硫化鋅核殼結構奈米柱與其光學性質研究

The structural and optical properties of ZnO-ZnS core-shell nanorods grown in vacuum

饒益智(Yi-Chih Jao)

指導教授 ： 洪魏寬

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2010年)

摘要

本論文主要研究ZnO-ZnS核殼結構的製作與光學特性。首先利用脈衝雷射蒸鍍法(PLD)在c面Al2O3基板上製作ZnO緩衝層。接著利用高溫爐的物理氣相傳輸法，長出準直均勻的ZnO奈米柱。最後再次利用PLD，在真空下進行ZnS包覆於ZnO奈米柱。
對ZnO奈米柱，經由X-ray繞射儀(XRD)，只有發現很強的ZnO(0002)的峰值。室溫光激螢光光譜(PL)量測觀察，可發現近帶隙發光於3.28eV，且在綠光波段區間，並無發現由氧空缺或鋅間隙所造成的深能階放射。拉曼光譜有ZnO的E2(high)峰值，未發現在缺陷光有關的E1(LO)峰值。
對ZnO-ZnS奈米結構，隨著基板溫度越低，由掃瞄式電子顯微鏡觀察厚度有隨著變厚和能量散佈光譜儀發現硫(S)的百分比變多趨勢相符。在XRD光譜中，除了原本的ZnO(0002)，多了ZnS(0002)的峰值。拉曼光譜量測也可發現ZnS的峰值。在室溫PL量測觀察，原先的ZnO奈米柱外，多了兩個很微弱的放射峰值，一個為ZnS 3.69eV的放射光，另一個可能屬於ZnO-ZnS的異質結構2.56eV綠光type-Ⅱ放光。

關鍵字

脈衝雷射蒸鍍法 ； 氧化鋅 ； 硫化鋅 ； 異質結構

並列摘要

In this research, wll-aligned ZnO-ZnS core-shell structured nanorods were synthesizd and their structural and optical properties were characrerized. The samples were prepared in three steps. First, ZnO buffer layer was fabricated on the c-plane sapphire substrate by pulsed laser deposition (PLD). Then well-aligned ZnO nanorods were grown on the ZnO buffer layer via physical vapor-phase transport process. In the last step, ZnS layer was coated onto the ZnO nanorods by PLD in vacuum to form the ZnO-ZnS core-shell nanorods.
For the bare ZnO nanorod samples, X-ray diffraction (XRD) pattern showed only the strong hexagonal ZnO(0002) diffraction peak. Photoluminescence (PL) measurement, performed at room temperature, showed only one emission peak at 3.28eV, which corresponds to the near band-edge emssion of ZnO, and not found oxygen vacancies and zinc interstitial with the ZnO deep-level emission (DLE). The Raman spectra obtained the peak of ZnO in the E2(high) and not found E1(LO) which related to DLE. The defect-related visible emission band was not observed.
For the ZnO-ZnS nanostructures, with temperature of the substrate lower, the thickness of the nanostructures along with thickening by scanning electron microscopy. And energy dispersive spectrometers (EDS) obtained the same tendency. The XRD patterns of the nanostructures shows original peak of ZnO, and a new peak of ZnS(0002) can be observed. The Raman spectra obtained the peak of ZnS. The room-temperature PL spectra of the synthesized ZnO-ZnS, which exhibited two new peaks at 3.69eV and 2.56eV related to ZnS and ZnO-ZnS heterostructure of the type-Ⅱ green emission respectively.

並列關鍵字

PLD ； ZnO ； ZnS ； heterojunctions

參考文獻

[27] 謝嘉民、賴一凡、林永昌、枋志堯，「光激發螢光量測的原理、架構及應用」，奈米通訊，第十二卷，第二期，2005，第29-30頁。

[1] Li J. , Zhao D. , Meng X. , Zhang Z. , Zhang J. , Shen D. , Lu Y. , Fan X. , "Enhanced Ultraviolet Emission from ZnS-Coated ZnO Nanowires Fabricated by Self-Assembling Method," Journal of Physical Chemistry B 110 (30), 2006, pp. 14685-14687.

[2] Lieber C. M. , "Nanoscale science and technology: Building a big future from small things," MRS Bulletin 28 (7), 2003, pp. 486-491.

[3] Yang Y. , Sun X. W. , Tay B. K. , Wang J. X. , Dong Z. L. , Fan H. M. , "Twinned Zn2TiO4 spinel nanowires using ZnO nanowires as a template," Advanced Materials 19 (14), 2007, pp. 1839-1844.

[4] Wu Y. , Xiang J. , Yang C. , Lu W. , Lieber C. M. , "Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures," Nature 430 (6995), 2004, pp. 61-65.