本論文主要研究利用金微米線方法製備單根二氧化錫奈米線裝置且探討藉由二氧化鈦奈米顆粒表面的修飾,二氧化錫奈米線裝置增強的光導特性。我們發現,在二氧化鈦奈米顆粒的幫助下,二氧化錫奈米線的光電流響應能夠增強50%。其主要機制可歸因於二材料間因導、價帶位置不同,所形成的第二型異質結構引起的載子分離過程。在第二型異質結構下,在二氧化鈦奈米顆粒內因光激發而產生的自由電子將遷移至二氧化錫奈米線的導帶上。同時二氧化錫奈米線內光激發產生的電洞將漂移至二氧化鈦奈米顆粒的價帶上。電子電洞對的分離不只降低他們的再結合機率同時遷移至二氧化錫奈米線導帶上的自由電子會大幅增加其光電流響應。此一研究顯示二氧化錫可用來製備高靈敏度的光偵測器。
Individual SnO2 nanowire-based device has been fabricated by the gold microwire mask method and enhancement of photon-sensing property through combining single SnO2 nanowire with TiO2 nanoparticles have been investigated. It is found that the sensitivity of photoresponse of SnO2 nanowire can be enhanced by up to 50%. The underlying mechanism can be attributed to the charge separation process taking place between TiO2 nanoparticles and SnO2 nanowire due to Type II band alignment. The charge separation of photoinduced electrons and holes greatly reduces their recombination probability and accordingly enhances the photoconductivity of TiO2-decorated SnO2 nanowire. The result implies that SnO2 nanostructure can serve as a highly sensitive photodetector.