掺杂对ZnO气敏性能的影响研究

ZnO是最早发现的金属氧化物气敏材料,对其掺杂一直是研究的一个热点.采用机械球磨法制备了22种不同掺杂的纳米ZnO气敏材料,通过乙醇、丙酮、苯的测试,系统对比了掺杂元素的化学性质,如离子半径、化合价、元素周期等对ZnO气敏性能的影响.掺杂元素的离子半径为0.072～0.088 nm时,传感器对被测气体的响应比掺杂其他离子半径的高.不同周期掺杂元素对ZnO纳米气体传感器的选择性有一定的影响.     

金属氧化物掺杂对ZnO气敏特性的影响

掺杂金属氧化物可大大提高ZnO的气敏特性,目前对这种性质的研究成为了研究热点.本文综述了掺杂金属氧化物对ZnO气敏特性的主要影响及机理;总结了目前研究中所掺杂的多种金属氧化物,并就各种掺杂物对ZnO气敏特性的作用进行了具体分析.     

紫光激发提高ZnO基半导体气敏传感器的敏感性能

以激光-感应复合加热法制备的纳米ZnO粉末为气敏基料,制作厚膜型的管状气敏元件,采用紫光(波长为370～395nm)激发,对无水乙醇进行了静态配气法的气敏性能测试.结果表明在紫光激发下,ZnO基半导体气敏传感器在较低的工作温度条件下对无水乙醇具有较好的气敏性能,而且随着紫光光强的增大,气敏性能提高.     

金属氧化物掺杂对TiO2气敏特性的影响

掺杂金属氧化物可显著提高TiO2的气敏这一特性，正逐渐成为研究的热点。本文综述了掺杂金属氧化物对TiO2气敏特性的主要影响及机理；总结了目前研究中所掺杂的十多种金属氧化物，并就各种掺杂物对TiO2气敏特性的作用进行了具体分析。     

掺杂和热处理对纳米ZnO薄膜气敏特性影响

用真空蒸发法在玻璃和单晶硅片上制备纯Zn和掺杂Zn薄膜，然后在高于450℃条件下进行氧化、热处理（玻璃衬底）获得良好的纳米ZnO薄膜和掺杂ZnO薄膜。对单晶硅衬底上制备的纯Zn薄膜在高于800℃温度条件下进行液态源掺杂，获得掺B和P纳米ZnO薄膜。实验表明，掺杂和热处理使纳米ZnO薄膜的结构、导电性能得到改善，有效地降低了纳米ZnO薄膜的电阻，同时薄膜的气敏特性也得到较大的改善。     

CeO2掺杂对ZnO薄膜气敏特性的影响

ZnO薄膜进行CeO2掺杂,研究掺杂含量和热氧化对薄膜结构、表面、晶粒尺寸及气敏特性的影响.结果显示,用热蒸发制备的高纯Zn膜经500℃热氧化,获得c轴取向ZnO多晶薄膜.掺CeO2可抑制晶粒生长使颗粒细化平均粒径减小,同时改善了ZnO薄膜的体相化学计量比,Zn与O的比例从未掺杂时1∶1.28降到1∶1.191.XPS...     

激光烧结纳米ZnO 气敏传感器制备及其气敏特性研究

以激光-感应复合加热法制备的纳米ZnO为原料，用激光烧结法制成的气敏传感元件，对乙醇、丙酮等五种挥发性有机化合物的敏感性进行了测定，同时又对所制成的传感元件作了SEM分析。实验表明，采用激光烧结的纳米ZnO较之电炉烧结的敏感度高，孔洞细小、孔隙率增多；且随着激光加工功率的提高，达到最大敏感度的温度却有所降低。     

Al2O3-La2O3共掺杂对ZnO纳米粉体气敏性能的影响

采用溶胶-凝胶法制备了ZnO和掺Al、掺La与Al—La共掺的ZnO纳米粉体。利用X射线衍射仪、透射电镜对材料的结构进行了表征：研究了不同掺杂对材料的气敏性能的影响。研究表明：发现Al或La掺杂均使ZnO对体积分数0．005％的Cl2的灵敏度有很大的提高,但Al-La共掺使ZnO的最佳工作温度从单掺的290℃降到200℃。     

ZnO系半导体陶瓷气敏传感器的进展

本文综述了ZnO系气敏半导体材料的发展慨况,讨论了元件的结构与气敏效应的关系,评述了解释ZnO系气敏材料性质的敏感机理,探讨了目前存在的问题及今后的发展方向。     

用溅射法制备ZnO薄膜丙酮气敏传感器

本文首先扼要介绍了ZnO的晶体结构以及作为压电、压敏、发光、透明导电薄膜的用途.还介绍了两种溅射方法制备ZnO薄膜.研究了ZnO薄膜的气敏性,发现经适当处理后仅对丙酮有择优气敏性.     

Ethanol gas sensor based on Al-doped ZnO nanomaterial with many gas diffusing channels

ZnO nanomaterial with multi-microstructures is synthesized by using normal pressure thermal evaporation and then doped with different Al₂O₃ contents by grinding in an agate mortar. The as-prepared Al-doped ZnO nanomaterials are characterized by X-ray diffraction and scanning electron microscopy. The characterization results show that all the compounds are wurtzite with hexagonal structure and are well crystallized. Channels/connecting holes arising from many kinds of ZnO microstructures are abundant. Both annealing and Al₂O₃-doping contributes to an increase in the quasi-one-dimensional and tri-dimensional microstructures. The as-prepared Al-doped ZnO nanomaterials show excellent gas responses to ethanol. The sensing mechanism of the ZnO-based nanomaterials with multi-microstructures is further analyzed by using the Effective Specific Surface Model. Excellent sensitivity (200) companied with short response time (8 s) and recovery time (10 s) to 3000 ppm ethanol is obtained with a ZnO-based sensor with 2 at.% Al₂O₃ at the operating temperature of 290 °C after the sensor is annealed at 500 °C.     

基于微接触印刷的ZnO紫外传感器特性研究

采用微接触印刷技术和水热生长方法在硅基底上实现了ZnO种子层的图案化转移与纳米线阵列的可控制备。利用X射线衍射(XRD)、能量色散谱(EDS)和扫描电子显微镜(SEM)等测试手段对制备的ZnO纳米线晶体结构、化学组分以及表面形貌进行了表征,并对制备的ZnO纳米线传感器进行了紫外特性测试。测试结果表明:随着紫外光强度的增加,传感器的光暗电流比和光响应度也随之增加。当紫外传感器偏压在4.5 V时,其光暗电流比为80.8,响应度可达4.05 A/W。     

类积木状ZnO气体传感器的制备及其气敏特性研究

采用水热法合成了类积木状ZnO纳米结构,利用X射线衍射仪(XRD)、X射线能谱分析仪(EDS)和扫描电子显微镜(SEM)对制备的ZnO纳米结构的物相、化学组分及微观形貌进行了表征与分析。对基于ZnO纳米结构的气体传感器进行甲烷气敏特性测试,测试结果表明:该传感器的最佳工作电压为5 V,在该电压下对体积分数为200×10-6甲烷气体的灵敏度可高达55.4%,最低检测限为1×10-6。     

Nanostructural ZnO based coplanar gas sensor arrays from the injection of metal chloride solutions: Device processing, gas-sensing properties and selectivity in liquors applications

A new coplanar gas sensor array of ZnO was fabricated by injecting different volumes of 0.01 mol/L AlCl₃, CuCl₂, SnCl₄, TiCl₄, PdCl₂ and WCl₆ solutions and post treatment to improve the selectivity in liquor. The new four-sensor array was optimized by maximizing Sum of Euclidean distances (SED) of the gases of liquor. The morphology of films was characterized by field-emission scanning electron microscopy (FESEM). The results showed that ZnO nanostructures were formed on the surface of films after the injecting process. Nanowires, 100 nm in diameter and 3 μm in length, were found when the solutions included AlCl₃, CuCl₂, SnCl₄ and PdCl₂. However, when the injecting solution was TiCl₄, nanotowers with 500 nm in diameter and 4 μm in length appeared. No new structures appeared when the WCl₆ solution was injected. The results of testing gases of liquor revealed that the injecting process could improve the response of the sensors array effectively. Through calculating the value of the SED, the best array was confirmed whose SED value would be three times the worst one.     

Pinecone-shaped ZnO nanostructures: Growth, optical and gas sensor properties.

Pinecone-shaped ZnO nanostructures have been fabricated on Si substrate by pulsed laser deposition. The scanning electron microscope images showed that pinecone-shaped ZnO nanostructure was 6-fold symmetry and has the rough surface on one end. X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy indicated that the ZnO nanostructures have high crystal quality and a large amount of surface states. Compared with ZnO nanowires and nanobelts, the oxygen gas sensor based on pinecone-shaped ZnO nanostructures has excellent selectivity, fast response and recover, and lower operating temperature. Meanwhile, the response properties are very stable over several circles.     

基于环形微热板的ZnO微气体传感器设计

提出一种新型的设有环形结构微热板的硅基ZnO微气体传感器。利用ANSYS软件,将环形电极结构与传统的蛇形结构进行温度分布的模拟仿真,发现该结构能供给传感器更高的温度且中心温度分布均匀,进而解决了现有传感器功耗大的缺点。通过对RF磁控溅射ZnO薄膜的工艺摸索,得出了适宜作气敏薄膜的制备参数。该传感器在250℃下对（200-1000）×10-6CH4气体有很好的响应。     

Fabrication and gas-sensing properties of hierarchically porous ZnO architectures

Hierarchically three-dimensional (3D) porous ZnO architectures are synthesized by a template-free, economical aqueous solution method combined with subsequent calcination. First, the precursors of interlaced and monodisperse basic zinc nitrate (BZN) nanosheets are prepared. Then calcination of the precursors produces hierarchically 3D porous ZnO architectures composed of interlaced ZnO nanosheets with high porosity resulting from the thermal decomposition of the precursors. The products are characterized by X-ray diffraction, thermogravimetric-differential thermalgravimetric analysis, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller N₂ adsorption-desorption analyses. The BET surface area of the hierarchically porous ZnO nanostructures was calculated to be 12.8 m² g⁻¹. Compared with ZnO rods, the as-prepared porous ZnO nanosheets exhibit a good response and reversibility to some organic gases, such as ethanol and acetone. The responses to 100 ppm ethanol and acetone are 24.3 and 31.6, respectively, at a working temperature of 320 °C. These results show that the porous ZnO architectures are highly promising for gas sensor applications, as the gas diffusion and mass transportation in sensing materials are significantly enhanced by their unique structures. Moreover, it is believed that this solution-based approach can be extended to fabricate other porous metal oxide materials with a unique morphology or shape.     

氧化锌纳米棒/单晶硅的酒精传感器研究

首先采用射频溅射在单晶硅(Si)上制备氧化锌(ZnO)薄膜,作为生长ZnO纳米棒的晶种层,再在水热条件下生长ZnO纳米棒.X射线衍射、X射线能量色散谱,扫描电镜及室温光致发光谱对样品的物相结构、成分、表面微观形貌和晶体缺陷进行了表征.结果表明合成的ZnO纳米棒是六方纤锌矿结构,长径比较高,结晶良好.研究了ZnO纳米棒/单晶Si传感器在空气和酒精气体中的电压-电流(Ⅰ-Ⅴ)特性,阻抗谱及响应-恢复时间.该传感器在+6 V的偏置电压下,其电阻在0.08 g/L酒精气体中下降71%,响应时间小于1 min,可以作为一种新型的酒精气体传感器.