以原子力顯微術奈米微影製作單一氧化鈦奈米點紫外光感測器

Single Titanium Oxide Nanodot Ultraviolet Light Sensor Created by Atomic Force Microscopy Nanolithography

由於半導體氧化物奈米材料具有特殊的物理與化學特性，有很多應用的可能性，尤其是在感測領域，近年來吸引了許多科學家投入研究。本文介紹以原子力顯微術奈米微影方法，製作單一氧化鈦奈米點感測器。首先製作單一鈦奈米線，並連接金電極，接著再製作單一氧化鈦奈米點，而形成金屬－半導體－金屬結構，並應用於紫外光感測。感測原理是由於紫外光照射下，氧分子在氧化物奈米點表面的脫附，而造成導電性變化。選擇奈米點位置在鈦奈米線中間或其與電極接面，可製作出歐姆型（ohmic）和蕭特基（Schottky）型兩種類型紫外光感測器，而後者靈敏度遠高於前者。除了紫外光感測外，此種氧化物奈米點感測器也可應用於氣體或化學感測，而成為一多功能的奈米感測器。 Recently, semiconductor oxide nanomaterials have drawn much research attention because of their extraordinary physical and chemical properties. Applications in a wide range of research areas have been reported, especially in the field of sensing. In this article, we report on the fabrication of a single titanium oxide nanodot(ND) nanosensor by atomic force microscopy nanolithography. A single titanium nanowire and gold contact electrodes are first created. A titanium oxide ND is then generated, which becomes a metal-oxide-metal structure, and can be used for detecting ultraviolet(UV) light. The detection mechanism is based on the desorption of oxygen molecules on the ND surface upon UV irradiation, which in turn increases the conductance. Two types of nanosensors, namely ohmic and Schottky, have been obtained by selecting oxidation regions in the nanowire and at the gold-titanium interface. The latter has a much higher sensitivity than that of the former. In addition to UV light sensing, the ND sensor can also be used for gas or chemical sensing and becomes a multi-functional nanosensor.