摻雜銻之氧化鋅奈米線的合成及其光學與電子傳輸特性之分析

Abstract

本研究成功地以熱蒸鍍法配合VLS成長機制，在矽(100)基板上合成出摻雜銻之氧化鋅奈米線，藉由控制不同載流氣體流量、基板溫度與腔體壓力去探討其對奈米線形貌的影響。在載流氣體流量60 sccm，通以氧氣5 sccm，基板溫度為650℃，調控腔體壓力在3 torr的條件下，可以得到密度最高、長寬比高的摻雜銻之氧化鋅奈米線，長度可達10-20 μm，成長方向為﹝ ﹞。利用螢光光譜的量測，可以觀察到摻雜銻之氧化鋅奈米線發光主要有兩個波長，380 nm與500 nm﹔與純氧化鋅奈米線比較，摻雜銻後，氧化鋅的近能隙吸收波長（NBE）峰值會有紅位移的現象，這是因為銻摻雜進去造成能帶的降低所導致。利用黃光與電子束微影技術製作量測摻雜銻之氧化鋅奈米線的電性試片，得到良好的歐姆接觸，計算電阻率約為1.727*10-2 (Ω cm)，並進一步量測其場效電晶體，可觀察其為一種P型半導體的特性，計算其載子遷移率為21.61 cm2/Vs、載子濃度為5.81*1017 cm-3。最後將之應用於紫外光感測器，可以看到依據紫外光的開關，電流有明顯的上升與下降。

In this work, we have successfully synthesized Sb-doped p-type ZnO nanowires (NWs) on Si (100) by using the process of thermal evaporation and vapor-liquid-solid method. The effect of carrier gas flow, substrate temperature and chamber pressure on the growth were discussed. Photoluminescence spectra of as-synthesized Sb-doped ZnO NWs were measured, which reveal a strong UV emission and a broad green emission. Comparing with pure ZnO NWs, the UV emission red-shifted about 54 meV, which can attribute to Sb doping reduce the band gap. The electrical properties of Sb-doped ZnO NWs devices prepared by the electron-beam lithography were investigated. The resistivity is about 1.727*10-2 (Ω cm). The devices exhibited the p-type semiconductor characteristic, the carrier mobility is 21.61 cm2/Vs, and carrier concentration is 5.81*1017 cm-3. Finally, we shows the potential application of Sb-doped ZnO NWs for UV sensor. The current rise/drop obviously depend on light on/off, respectively.