Pd掺杂SnO_2纳米膜的制备及H_2敏感性能研究

Preparation and H_2 Sensing Characteristics of Pd-doped SnO_2 Nano-powders

以分析纯SnCl2.2H2O和PdCl2为主要原料,控制不同n(Pd2+)/n(Sn2+),利用溶胶凝胶-浸渍提拉法制备了Pd掺杂SnO2纳米膜。用XRD、AFM对样品的结构、形貌进行了分析,并测试了Pd掺杂SnO2纳米膜的阻温特性和对H2敏感性能。结果表明,Pd掺杂SnO2纳米膜平整而致密,表面椭球形粒子颗粒尺寸约为20nm;Pd掺杂SnO2为金红石型晶体结构,但Pd2+进入SnO2晶格代替八面体中部分Sn4+,导致其晶胞参数比未掺杂SnO2略小;Pd掺杂SnO2纳米膜的电阻随温度升高而减小,表现出n型半导体阻温特性;随着Pd掺杂比例的增大,元件的电阻增大,其对H2的灵敏度先增大后减小,当掺杂比例为1%时对H2灵敏度最高。

Pd doped SnO2 thin films were prepared by sol-gel method and dip coating process with analytically pure SnCl2·2H2O and PdCl2 at different n（Pd^2＋ ）/n（Sn^4＋ ） ratios. The phase transformation, structure and shape of samples were analyzed according to XRD and AFM. The resistance-temperature character and sensitivily in H2 atmosphere of the sensors were tested. The result indicated that Pd-doped SnO2 thin films were smooth and compact, and the size of superficial ellipsoidal particle was about 20nm. The crystal structure of Pd doped SnO2 was rutile lypc.The cell parameters of Pd doped SnO2 were a few smaller lhan that of pure SnO2 for Pd^2＋ entered into crystal lattice of SnO2 instead of Sn^4＋ in octahedron. The resistance of Pd doped SnO2 decreased with temperature increasing and that showed n type semiconductor resistance temperature characteristics. With Pd doping ratio increased, the components of the resistance increased, the sensitivity of the H2 then decreased when the doping ratio of 1%. the highest sensitivi ty of the H2.