Pd颗粒表面修饰ZnO纳米线阵列的制备及其气敏特性

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。

Preparation and Gas Sensing Characteristics of ZnO Nanowire Arrays Surface-decorated by Pd Particles

ZnO nanowire (NW) arrays were synthesized by chemical vapor deposition (CVD) method on SiO2/Si substrate.The Pd films with different sputtering time (0-150 s) were uniformly deposited on the surface of ZnO NWs and converted to Pd particles by annealing treatment at 800 ℃ in Ar gas, and then the gas sensing measurement was performed.The length of the NW is about 15 μm and the diameter is 100-500 nm.For ethanol gas, the optimal working temperature of all gas sensors is 280 ℃.The increase of the sputtering time (from 3 to 10 s) induces the increase of the number and size of Pd particles, and the response of gas sensor raises from 2.0 to 3.6.Further increase of the sputtering time (from 30 to 150 s) leads to significant increase of the size of Pd particles and the formation of the continuous film, resulting in the significant decrease of the response.All the sensors exhibit the best gas selectivity to H2 gas, and the better properties of the response and recovery time and the response stability are obtained.Finally, the influence mechanism of Pd particle surface decoration on the ZnO NW array gas sensors was discussed.