水熱法合成氧化鋅奈米線及應用於檢測紫外光之性能

Preparation of ZnO Nanowires by a Hydrothermal Process and the Performance of Nanowire-based UV Photodetectors

本研究是藉由介電泳動(dielectrophoresis)之方式將適合於電極間距長度之奈米線跨接於金電極之上，以製作成氧化鋅/金的蕭基式接觸(Schottky contact)。氧化鋅奈米線之長度可藉由在水熱法的合成過程中調整聚乙烯醇(PVA)的添加量加以控制。其原理是藉聚乙烯醇做為鋅離子之貯存裝置，並且在反應的過程中緩慢的釋放出鋅離子，藉以調控Zn(OH)4[2-]在溶液中的過飽和程度，而獲得不同尺寸之氧化鋅一維結構。將組裝完成之光檢測器元件，利用波長為365nm光強度為1.6mW/cm2之紫外光進行測試，反應時間(response time)約為4秒，靈敏度(responsibility)約180mA/W。

In the present study, PVA is employed as structure-directing agent, and can control the concentration of Zn2+ in reaction solution. The sizes of the ZnO wires can be tuned easily by controlling the addition amount of PVA, due to the sufficient concentration of Zn2+ ions chelated by PVA releasing to the reaction solution in hydrothermal process. The ZnO wires were aligned onto Cr/Au electrodes by dielectrophoresis process for fabricating Schottky photodetector. The response time and responsibility were found to be 4 s and 180 mA/W measured under a UV light (λ: 365 nm) with a power density of 1.6 mW/cm2.