以水浴法製作規則排列氧化鋅奈米柱的材料分析

Abstract

熱退火和摻雜常用來改善以水浴法生長之氧化鋅奈米柱晶體品質，本研究中，我們分析在不同熱退火和摻雜條件下所生長的氧化鋅奈米柱的材料及光學特性，我們呈現穿透式電子顯微鏡、高角度環形暗場像、能量散佈能譜儀、掃描式電子顯微鏡、背向散射電子及螢光發光譜量測的結果，發現在經過熱退火處理的樣品中會有孔洞產生，在高角度環形暗場像圖中可以在奈米柱中看到孔洞分佈有明顯的邊界從奈米柱底端延伸出來，不過會隨著退火溫度的增加而逐漸消失，另外在經退火樣品的光散發螢光頻譜中，觀察到其缺陷發光波段的發光強度會於退火溫度為200度及300度時下降，然而在退火溫度為400度及500度下其缺陷發光強度又會開始變強。以上的幾種現象很可能是因為氧化鋅奈米柱中的氫氧根離子團在退火過程中逸散所導致的結果。

The material and optical analysis results of ZnO NRs grown with the hydrothermal method under different annealing and doping conditions are investigated. The transmission electron microscopy (TEM), high-angle annular dark-field (HAADF), energy dispersive X-ray spectrum (EDX), scanning electron microscopy (SEM), backscattered electron (BSE), and photoluminescence spectra (PL) results of the ZnO NRs are demonstrated. Voids are observed in the samples after thermal annealing. Boundaries of void distribution extended from the NR bottom could be drawn after annealing. They gradually disappear as the annealing temperature is increased. The defect-band emission intensity in PL spectra is found to decrease at 200 and 300 o C in annealing temperatures and then increase again when annealed at 400 and 500 o C. Desorption of hydroxyl groups could be the cause for the above phenomena. In addition, polarity in the c-axis direction might attract hydroxyl groups during vertical-direction growth.