氧化鋅奈米梳的上轉換螢光

Upconversion Luminescence In ZnO Nanocomb

張振隆(Chen-Lung Chang)

指導教授 ： 沈志霖

中原大學/理學院/物理研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200318

摘要

本文主要分成兩部分，第一部分探討氧化鋅奈米梳的上轉換螢光光譜機制，首先利用室溫的光激螢光光譜證實鋁摻雜對氧化鋅可見光區螢光的影響。比較低溫( 15K )的光激螢光光譜與上轉換螢光光譜，觀察到兩個現象，紫外光區聲子震盪強度不同，可見光區螢光強度不同。接著變功率的光譜證明了，上轉換螢光光譜中電子是由兩顆光子激發形成紫外光區的螢光，由增加鋁的摻雜濃度可以證實，缺陷態多的氧化鋅上轉換螢光強度較強，證明缺陷態為電子再吸收光子能量的中間態，這讓我們清楚的知道缺陷在上轉螢光光譜中扮演重要的角色。
第二部分，利用變溫的光激螢光光譜與上轉換螢光光譜與Manoogian 和 Woolley建立的擬合公式( MW mode )，可以獲得激子與聲子間的耦合強度，證實上轉換螢光光譜中激子與聲子間耦合強度較弱，是因為雷射穿透深度與表面態的影響，讓激子有機會掉落至P能階再復合放光，使得上轉換螢光光譜中觀察到聲子震盪強度比較強，能量位置也比較高。

關鍵字

氧化鋅 ； 光激螢光

並列摘要

In this thesis, we have two parts to present. In the first part we investigated the upconversion luminescence (UCL) mechanism of zinc oxide (ZnO) nanocombs. The room-temperature photoluminescence (PL) shows that the Al-doping affects the visible luminescence of ZnO. Compared with PL and UCL spectra at the low temperature (15K), we observed the phonon-oscillation (luminescence) intensity in the ultraviolet (visible) region is different. The power-dependent UCL shows that the electrons are excited from the two-photon absorption process. Adding the density of defect levels can increase the intensity of the UCL. Thus, the intermediate levels in the upconversion process are the defect levels in the band gap of ZnO. This indicates that the defect levels play a very important role in the UCL of ZnO nanocombs.
In the second part, we investigated the exciton-phonon coupling by the temperature-dependent PL and UCL spectra, and by fits of the Manoogian and Woolley mode (MW mode). The peak energy in UCL is larger than that in PL, arising from pronounced the phonon replica as well as the P-band emission.

並列關鍵字

PL ； ZnO ； UCL

參考文獻

[1] 中原大學物理系碩士學位論文, “以化學氣相沉積法成長鋁摻雜氧化鋅奈米柱之研究”, 研究生：唐緯群

[3] D. M. Bagnall, Y. F. Chen, Appl. Phys. Lett., 73, 1038 (1998).

[5] Bhupendra K. Sharma, Neeraj Khare, D. Haranath, Solid State Communications 150, 2341–2345 (2010).

[8] Y.S. Kim, C.H. Park, Phys. Rev. Lett. 102, 086403 (2009).

[10] Feihong Jiang, Jun Zhang, Appl. Phys. Lett., 98, 181912 (2011).