Tailored Growth Of SiC Nanowire Arrays And Their Field Emission Properties

Field emission (FE) is one of the intrinsic characteristics of low dimension nanometer materials and becomes one of the frontier and hot issues on current international research, owning to its broad application prospect in displays, vacuum electric, and so on. Due to its superior mechanical properties, excellent chemical stability, low thermal-expansion coefficient, high thermal conductivity and low electron affinity, silicon carbide (SiC), the third generation of wide bandgap semiconductor, is considered as one of excellent candidates for FE cathode materials.In the present work, research and development the FE cathode materials with excellent electron emission properties is considered as the goal. The growth and structure controlled of the well-alliged SiC nanowire arrays with sharp tips is achieved by explorating and tailoring the pyrolysis optimization, in order to realize the synergistic reinforcement of the ability of SiC nanostructures electron emission by seting the local field enhancement effect, increasing the number of electronic launch and tailoring the dopant.The SiC nanowires have been synthesized on the carbon paper via pyrolysis of polymeric precursors assisted by catalysts. The PSN precursor provided the Si and C source and the Ar atmosphere was introduced as the shielding gas. The n-type and p-type SiC nanowires with N-doped and B-doped have been synthesized introduced dopant during the whole pyrolysis process. Then the well-alliged SiC nanowire arrays with sharp tips have been grown on the 6H-SIC wafer substrates via pyrolysis of polymeric precursors assisted by catalysts. It realizes that the growth and the structure of the well-alliged SiC nanowire arrays can be controlled by exploring and optimizing the key technological parameters, such as substrate species, catalyst species and cooling rate.The n-type and p-type well-alliged SiC nanowire arrays with sharp tips field emission cathode was synthesized. The field emission properties results showed that the turn-on field (E10) of n-type SiC nanowire arrays with sharp tips was 1.50 V/μm under room temperature (RT), and it decreased to 0.94 V/μm when the temperature was up to 500 ℃, implying their excellent ability of electron emission.The highly oriented SiC nanoarrays were grown by adjusting the thicknesses of Au films used as the catalysts. The densities of the nanoarrays were tunable to be-2.9 X 107,-4.0×107 and -5.7 ×107 nanowires/cm2 by controlling the Au film thicknesses of 50,70 and 90 nm, respectively. The measured field emission characteristics disclosed that the turn-on fields of the samples could be tailored to be of ～1.79,～1.57 and ～1.95 V/μm with the increase of the densities, suggesting that a suitable nanowire density could favor the enhanced electron emission from the SiC nanoarrays with improved emission sites and limited field screening effects. The E10 of p-type SiC nanowire arrays with sharp tips was 1.92 V/μm under RT, and it decreased to 0.98 V/μm when the temperature was up to 500℃. The current fluctuations under RT and 200℃ were ca.-6.5% and -7.8%, respectively. The slightly changed current fluctuations between RT and 200℃ confirmed that the present SiC nanoarrays with B dopants had excellent high temperature stability and can be serviced under high temperatures. The n-type and p-type SiC nanowire arrays obey the traditonal F-N from RT to 500℃ and their Eto decrease with the increase of temperature can attribute to the work functions of SiC decreased with the increase of temperature.