Several - Dimensional Nanostructure Materials Preparation And Application Of Research

Recently, one-dimensional nanostructure materials have been widely investigated due to their superior physical, chemical and mechanic properties. Especially the application researches including properties characterization, device assembly and device performance evaluation has attracted enormous attention in the field of nanotechnology. In this dissertation, we focused on two materials:M-TCNQ and ZnO. The basic optic and electric properties of nanostructures of these materials has been investigated, and corresponding device prototype employing such properties has been fabricated. In details, the whole dissertation consists of the following parts:M-TCNQ 1D nanostructures with various morphologies were synthesized via vapor transportation in vacuum method and aqueous solution route. The morphologies and crystalline structures were then characterized by SEM, XRD and Raman spectrum. And the growth mechanism has also been discussed.We then investigated the electric transportation characteristics of as-obtained individual Cu(TCNQ) nanowire. It is indicated that Cu(TCNQ) nanowire exhibited typical electric switching phenomena, and the switching threshold voltage is in linear relationship with the effective length of the nanowire between two electrodes. Furthermore, the temporal response of the switching process has also been researched. It has been observed that the local heating of the current in a single nanowire will greatly modulate the switching. In addition, the switching process is found to be unvatile under ultra-low temperature.On the basis of the electric switching properties, we fabricated two types of over-voltage protector using Cu(TCNQ) nanowires. The main building blocks of the two structures are photoresist hole array and AAO template, respectively. When parallel connecting to a protected component (10 kΩresistor in our experiment), the protector can efficiently bypass the large current resulting from the surge voltage.The field emission properties of M-TCNQ nanowires array has also been investigated, which exhibited that the nanowires can output emission current with the order of mA/cm2 in the present of Metal buffer layer. Afterwards, the field emitter with the structure of patterned ITO/Cu buffer layer/Cu(TCNQ) nanowires was fabricated. The fluorescence lighting experiment showed that the fluorescence pattern can reach the maximum luminance of 810 cd/m2.Two types of ZnO 1D nanostructures:ZnO nanowires and ZnO nanotetrapods has been synthesized by vapor phase method and solution method. The morphologies and crystalline structures were then characterized. The growth mechanism and fabrication process were also discussed.The back-gate typed field effect transistor (FET) was then assembled using as-obtained individual ZnO nanowire via lift-off photolithography. After the measurement of electric properties of such FET, the semiconductor parameters of the ZnO nanowires has been calculated with carrier concentration n= 1.15×108 cm-1 and electron mobilityμe=14.4 cm2/Vs. In addition, the cut-off limit frequency of the FET was measured to be 1585 Hz, and the capacitance between the source and drain was 25.4 pF. On the other hand, the ZnO naowire FET exhibited strong ultraviolet photoelectric response. Interestingly, the gate voltage can modulate the photocurrent and the photo relaxation time.Two types of chemical sensor were achieved utilizing as-prepared ZnO 1D nanostructures. The first one was the ethanol gas sensor using pellet of ZnO nanotetrapads, which shows intensive sensitivity to ethanol gas at 275℃。By comparison, we doped the ZnO nanotetrapads with Ti element. It is observed that the sensitivity of Ti doped ZnO nanotetrapads exceeded the pure ZnO sample with one order. In particular, the Ti:ZnO sensor obtained a sensitivity of 3.4 to mere 10 ppm ethanol. Moreover, Ti:ZnO sensor showed both faster response and faster recovery in the sensing process. This is attributed to the Ti4+ generally substitutes the Zn2+ partially in the ZnO crystallites and forms Ti donors, where more conductor electrons might be originated from.The second one is the mirco-chamber ZnO nanowire gas sensor. Here the device consisted of a mirco-chamber with a volume of 1 cm3 for the exchange of target gas and a single ZnO naowire based sensor. The sensor exhibited sensitivities of 1.3 and 1.5 to 5000 ppm O2 and ethanol, respectively. Moreover, the device showed a fast response within 10 s and recovery within 50 s towards these kinds of gas. These results were obviously superior to those of bulk materials and thin film structures. We owing this improvement to the local current heating effect of nano-scaled materials. A field emission displayer (FED) prototype with 72 X 72 pixels array using as-obtained ZnO nanotetrapods was fabricated via screen painting and low-melting glass powder packaging. We successfully achieved the display of scrolling Chinese characters using the FED prototype.