Preparation And Fifld Emission Characteristics Of Al-doped ZnO Nanowires

Field emission display(FED) is a novel flat panel display device.It has the advantages of low power consumption, high brightness, high resolution and good environment adaptability. Field emission cathode array(FEA) is the focus of FED technology. The performance of FED is directly determined by the field emission properties of FEA.As a FEA material, one-dimensional ZnO nanomaterial is widely researched because of its low preparation cost, the large length/radius ratio and the radius of curvature of the nanometer level. However, the conductivity of the intrinsic ZnO is low, which limits the field emission properties of ZnO. So this issue aims to improve the field emission properties of ZnO nanowire arrays. ZnO is doped by Al under the reasonable control of the density of ZnO nanowire arrays and the morphology of the tip of ZnO nanowires, to enhance the conductivity of ZnO nanowire arrays and improve current density to meet the requirements of the emission capabilities of FED.Al-doped ZnO(ZAO) nanowires were successfully prepared on the silicon substrate by hydrothermal method. To study its field emission properties, the main experiments and results are as follows:1. The ZnO seed layer was prepared by magnetron sputtering.The deposition rate was 18nm/min and the thickness uniformity of ZnO thin film was good. In addition we got the best parameters of magnetron sputtering process.2. The undoped ZnO nanowires were prepared by the hydrothermal method. The best hydrothermal parameters had been found: concentration of 0.025 M, growth time of 4 hours, the seed layer sputtering time of 30 ~ 45 s.3. The undoped ZnO nanowires with the smaller diameter were prepared by hydrothermal kyropoulos method. The turn-on field was 5.2 V/μm and the maximum current density was 243 μA/cm2.4. The field emission properties test of ZnO nanowires array with different concentration showed that the high concentration could increase the effective emission area of nanowires array, but it was not enough to offset the deterioration of properties caused by the shielding effect. The higher the concentration, the worse the field emission properties5. Through the successful preparation of ZAO nanowires array with the seed growth method, nanowires were parallel to(002) crystal orientation and the average diameter was 50 nm. ZAO nanowires array with Al-dosages of 4 at% had the best field emission properties. It exhibited the higher current density of 4.7 mA/cm2, larger field-enhancement factor of 1834, lower turn-on field of 0.65 V/μm, and lower threshold field of 6.7 V/μm, which met the demand of the small size FED.The research shows that, Al-doping can effectively improve the field emission properties of the ZnO nanowires array, which provides a new way for the expansion of one-dimensional ZnO nanowires array applications in the field of FED.