本文為奈米碳管電子元件之製備、特性研究與應用。以低溫製備的方式將奈米碳管結合奈米微機電技術製作出奈米碳管電子元件,探討其電子傳遞之物理特性。奈米碳管擁有優良的電子傳遞特性,製作為奈米碳管電子元件後,裸露在外的奈米碳管對於外界環境相當靈敏,非常適合用來做為感測元件。在實驗製作方面,我們以退化型之重掺雜矽基材作為背閘極,基材上方長出100 nm之氧化矽絕緣層,配合微影製程定義鈀(Pd)電極於介電層上,再利用介電泳力將奈米碳管接合至電極上方,完成奈米碳管電子元件之製作。本文將商用之單壁奈米碳管粉末溶解於十二烷基硫酸鈉(SDS)有機溶劑中,使之裹上一層有機高分子之膠束,並以物理方法將奈米碳管純化與單根化,在特定的介電泳力參數控制下,成功地製作出擁有場效應特性且電流的ON-OFF達103~104個等級之奈米碳管場效應電晶體與電阻特性之奈米碳管電子元件。在去除裹覆於碳管表面之SDS分子後,能夠降低奈米碳管與接觸金屬之接觸電阻並且減少電子散射的機會,進而改善奈米碳管電子元件特性,提升”ON”電流值約6倍。 本論文將製作好的奈米碳管場效應電晶體接上不同序列但相同鹼基之單股去氧核醣核酸(ssDNA)分子,藉由奈米碳管與ssDNA分子間的π-π堆疊作用力讓ssDNA上的鹼基接觸到奈米碳管管壁表面,可作為常溫操作、高靈敏度及快速自我回復之氣體感測器裝置。
In this thesis, we will discuss the properties, fabrication, and applications of the carbon nanotube electronic devices. Carbon nanotube (CNT) electronic devices were fabricated by low-temperature technique combined with nano-electro-mechanical technologies (NEMS), and the physics of electrical transport will be investigated. Since CNTs have superb mechanical and electrical properties, the fabricated CNT electronic devices with bare CNT channels are very sensitive to the environments which can be used for sensor devices. Otherwise, the low-temperature fabrication can integrate CNTs with CMOS circuitry to disclose a processor-inside sensor system. In the experimental processes, the degenerately p-doped silicon wafers with 100 nm silicon oxide were used as the back gate; palladium (Pd) metal electrodes were formed by photolithography combined with lift-off technique, and finally deposited and aligned CNTs on the predefined electrode pairs to complete devices fabrication by using alternating current dielectrophoresis (AC-DEP). Commercial as-prepared single-walled carbon nanotube (SWCNT) soot was suspended in sodium dodecyl sulfate (SDS) solution and the nanotubes would be coated with SDS micelle, followed by physical purification and debundling treatments, these SWCNTs were manipulated by AC-DEP with experimental control and successfully fabricated carbon nanotube field-effect transistors (CNTFETs) with on/off-state current ratios of 103~104 order and other CNT devices with resistor characteristics. After removing SDS residuals coated on SWCNTs, the formation of an improved metal-CNT contact and reducing the probabilities of carrier scattering resulted in improving performance of the CNT devices and also can have “ON” current promoted by 6 factors. The three fragmented (20-mer) single-stranded DNA (ssDNA) sequences are composed of identical bases A, T, C respectively and all were dropped on the fabricated CNTFETs, and the bases of ssDNA are extended from the backbone and stacked onto the sidewall of SWCNTs via π-π-stacking interaction. These CNTFETs decorated with ssDNA can be utilized as a gas sensor with high sensitivity, self-regenerating and working in room-temperature environment.