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采用化学气相沉积(CVD)方法在SiO_2/Si衬底生长了ZnO纳米线阵列,纳米线长约为15μm,直径为100~500 nm。通过改变溅射沉积时间(0~150 s),在ZnO纳米线表面包覆了不同厚度的Pd薄膜。在Ar气氛中,经800℃高温退火后,制备出Pd颗粒表面修饰的ZnO纳米线阵列并对其进行了气敏测试。对于乙醇而言,所有传感器最佳工作温度均为280℃。溅射时间的增加(3~10 s)导致ZnO纳米线表面Pd纳米颗粒数量及尺寸增加,传感器响应值由2.0增至3.6。过长的溅射时间(30~150 s)将导致Pd颗粒尺寸急剧增大甚至形成连续膜,传感器响应度显著降低。所有传感器对H2均表现出相对较好的选择性,传感器具有较好的响应-恢复特性和稳定性。最后,探讨了Pd颗粒表面修饰对ZnO纳米线阵列气敏传感器气敏特性的影响机制。
ZnO nanowire arrays were grown on SiO 2 / Si substrates by chemical vapor deposition (CVD). The length of the nanowires was about 15 μm and the diameter was about 100-500 nm. By changing the sputtering deposition time (0 ~ 150 s), different thickness Pd films were coated on the surface of ZnO nanowires. After annealed at 800 ℃ in Ar atmosphere, ZnO nanowire arrays with Pd particles were prepared and gas-sensitively tested. For ethanol, the best operating temperature for all sensors is 280 ° C. The increase of sputtering time (3 ~ 10 s) led to the increase of the number and size of Pd nanoparticles on the surface of ZnO nanowires, and the sensor response increased from 2.0 to 3.6. The long sputtering time (30-150 s) will result in the rapid increase of Pd particle size or even the formation of continuous film, the sensor responsivity is significantly reduced. All sensors showed a relatively good selectivity for H2 and the sensor had good response-recovery characteristics and stability. Finally, the mechanism of the influence of Pd particle surface modification on the gas sensing properties of ZnO nanowire array gas sensors is discussed.