- 學位論文
以水溶液法在氮化鎵基板生長氧化鋅磊晶膜
Growth of ZnO Nanorod Epilayer on GaN/Sapphire by aqueous solution deposition
摘要
透明、高電子遷移率薄膜電晶體是先進顯示器發展之關鍵，因其透明則亮度高，可以低功率操作，因電子遷移率高反應速度快，可供高解析度顯示器使用，近年來迅速發展之金屬氧化物如氧化鋅(ZnO)可滿足這些要求。 在本研究中使用液相沉積法於氮化鎵基板上生長ZnO奈米柱陣列並使其合併成氧化鋅磊晶層，探討於p-type氮化鎵基板上所生長之磊晶層物性、光性、化性與電性。在X光繞射分析(XRD)下得知在笑氣退火後，可以得到結晶良好的ZnO磊晶層。在光激螢光(PL)的分析可以得到，未退火的氧化鋅磊晶層於紫外光激發峰值約為376 nm，而在綠光(Green band)區於550~650 nm會有峰值出現，此為氧化鋅之鋅間隙與氧空缺的內部缺陷，由實驗得知，在笑氣300 °C退火後可以填補氧化鋅內部缺陷進而改善結晶品質。在原子力顯微鏡中(AFM)得到連續且平滑的磊晶層，最後再使用掃描式電子顯微鏡(SEM)觀察ZnO之表面、切面型態，並以霍爾量測(Hall measurement)分析電特性。 為了提高柱間之合併程度及合併速度，於是加入硝酸溶液生長氧化鋅磊晶層，並與未加入硝酸溶液之氧化鋅磊晶層作物性、光性、化性與電性之比較。
並列摘要
Transparent and high electron mobility thin film transistor (TFT) is the key technology for modern displays. The transparency can enhance the brightness of display at lower operated power. The high electron mobility can enhance the switching speed and resolution. Metal oxides, for example zinc oxide (ZnO) can meet those requirements. In this study, we grow ZnO nanorod array and transform into ZnO epilayer on p-type GaN/sapphire substrate by aqueous solution deposition (ASD). The XRD analysis shows the good crystalline quality of ASD-ZnO epilayer after N2O annealing. The PL analysis of ZnO epilayer shows the typical emissions of near band edge excitonic emission (NBE) peak at 376 nm and deep level emission (DLE) (550~650 nm) bands. The deep level emission (550~650 nm) is composite to O vacancies and Zn interstitial, the emission is improved after N2O annealing at 300 °C. In addition, AFM shows ASD-ZnO can obtain a smooth and continuous epilayer. The morphology and thickness of ZnO epilayer we obtained by the analyses of FE-SEM and the electrical properties of ZnO epilayer were characterized by Hall measurement. In order to increase the growth rate of epilayer and enhance the merge of ZnO nanorods, HNO3 solution incorporation is promising for the growth of ZnO epilayer transformed from ZnO nanorod array. ASD-ZnO epilayer with and without HNO3 incorporation is compared in this study.