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钨氧化物纳米线在高灵敏度低功耗气体传感器中极具应用潜力,且通过掺杂改性可进一步显著改善其敏感性能.本文以WCl6为钨源,NH4VO3为掺杂剂,采用溶剂热法合成了钒掺杂的W18O49纳米线.利用扫描电镜、透射电镜、X射线衍射、X射线光电子能谱仪表征了纳米线的微结构,并利用静态气敏性能测试系统评价了掺杂纳米线的NO2敏感性能.研究结果表明:五价钒离子受主掺杂进入氧化钨晶格结构,抑制了纳米线沿轴向的生长并导致了纳米线束的二次集聚;室温下,钒掺杂W18O49纳米线接触NO2气体后表现出反常的p型响应特性;随工作温度逐渐升高至约110 C时,发生从p型到n型的电导特性转变;该掺杂纳米线气敏元件对浓度低至80 ppb(1 ppb=10 9)的NO2气体具有明显的室温敏感响应和良好的响应稳定性.分析并探讨了钒掺杂W18O49纳米线的高室温敏感特性及其p-n电导转型机理,认为钒掺杂W18O49纳米线在室温下的良好敏感响应及反常p型导电性与掺杂纳米线表面高密度非稳表面态诱导的低温气体强吸附有关.
Tungsten oxide nanowires have potential applications in high-sensitivity and low-power gas sensors, and their sensitivity can be further improved by doping modification.In this paper, WCl6 is used as a tungsten source and NH4VO3 as a dopant, The vanadium-doped W18O49 nanowires were synthesized.The microstructures of the nanowires were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The static gas sensitivities of the W18O49 nanowires were also evaluated. NO2 sensitive properties.The results show that: pentavalent vanadium ions doped into the tungsten oxide lattice structure, inhibiting the growth of nanowires along the axial direction and lead to the secondary agglomeration of nanowires; room temperature, vanadium-doped W18O49 nanometer When the contact gas contacts with NO2 gas, it exhibits abnormal p-type response. When the working temperature rises to about 110 C, the conductivity changes from p-type to n-type. When the concentration of n-type gas sensor is low The NO 2 gas with 80 ppb (1 ppb = 10 9) has obvious room temperature sensitive response and good response stability.The high room temperature sensitive properties of vanadium-doped W18O49 nanowires and their pn conductance transition mechanism were analyzed and discussed.The vanadium doped Miscellaneous W18O The good sensitivity response of 49 nanowires at room temperature and the abnormal p-type conductivity are related to the strong adsorption of low-temperature gas induced by the high-density and unsteady surface states of the doped nanowires.