Key Process For Nano-manipulation Of ZnO Nanowires And Its Sensing Application

With the rapid development of nanotechnology, a variety of new nanomaterials and and nanodevices, which the nanomaterials serve as the functional units because of their unique electrical and mechanical characteristic, have been born. However, the currently popular methods for testing the characteristic of nano-materials and assembling nanodevices are just relatively simple and rough, which some characterization instruments, such as semiconductor measurement system and atomic force microscopy, are directly abused. Therefore, it is urgent to develop nano-manipulation technology and system, which are independent and fully functional at making the mechanical and electrical test on nanomaterials and assembling nano devices.This thesis has developed a series of nano-manipulation methods and equipments, and used these to measure the mechanical and electrical characteristic of ZnO nanowire and fabricated strain sensor based on a single ZnO nanowire. The main content and inno-vative details are listed as below:The method of manufacturing long nano-manipulation fingers based on dynamic electrochemical etching reaction has been raised. The etching mechanism and the disci-pline of manufacturing technics have also been researched. A fully automatic equipment of manufacturing of manufacturing long nano-manipulation fingers with the length of2mm and the aspect diameter of less than200nm has been maken. The optimal manufacturing technics have been researched.The nano-welding technics according to the principle of electron beam induced dep-osition have been raised. In this nano-welding technics, the scanning electron microscope served as the basic equipment, the paraffin served as the precursor material, and the pre-cursor gas pumping part was omitted. This nano-welding could be achieved through the nanoscale amorphous carbon which was deposited by the resolvtion reaction of paraffin. The testing experiment has proven that the strain of this welding is as high as2.3xlO5Pa and is completely fit for nano-manipulation. The electrically driven nano-tweezers based on shape memory alloy has been innova-tively developed to achieve the clamp of nanomaterial. According to the analysis of elec-trothermal characteristic of the shape memory alloy spring, the electrically nano-tweezers actuated by the shape memory alloy has been developed and dynamics have also been re-searched and measured. In addition, the method of placing nanowires freely by electro-static force has also been raised. The model of electrostatic force applied on nanowires and the optimal placing technics parameters have been deeply researched.The electric characteristic of ZnO nanowires under strain has been researched and analysed, and the sensing model of ZnO nanowire under strain has been raised. The mean square error of this model has been proven to be less than0.5%through testing experi-ment. By this model, it was found that the gauge factor of Schottky contact was14times larger than that of Ohmic contact. This has direct significance on the assembly of the strain nanosensor based on ZnO nanowires.The technics of measuring the mechanical and electrical characteristic of ZnO nan-owires and packing and fabricating the strain sensor based on a single ZnO nanowire have been researched and raised based on the methods, equipments and model described above. The Young’s modulus and the electrical characteristic with and without strain of a single ZnO nanowire have been measured respectively. The strain sensor based on a single ZnO nanowire has also been packed and fabricated. Its gauge factor was448and the minimum measured strain was10-4, which was much better than the commercial strain sensor.The nano-manipulation technics and equipments researched in this thesis have a great application foreground in measuring the mechanical and electrical characteristic of nan-owire and fabricating nanodevices. The raised sensing model of ZnO nanowire has di-rective significance on revealing the mechanism of the electrical characteristic of the ZnO nanowire-metal stricture under strain and assembly of strain nanosensor.