平面型SnO_2微型传感器

所研制的平面型SnO_2微型传感器是用射频溅射制备超微粒SnO_2膜,和常规的硅平面工艺制作加热器和温度检测器,二者相容集成而制作的气敏器件。用AES、ESCA对SnO_2膜进行了分析,结果表明膜中并没有分离的Sn的成分。利用SnO_2膜接触不同气体表面电导会发生变化的特点,对器件进行了气敏特性测试分析。结果表明:SnO_2膜和Pd/SnO_2膜在200℃～300℃工作温度下对CH_4、CO、H_2、NO_2和H_2S等气体均有明显的敏感特性。当SnO_2膜表面掺入几十埃的Pd后,对上述气体     

超微粒氧化铁的制备与气敏性能的研究

本文采用PCVD法制备了纳米级的超微粒氧化铁气敏材料.用这种材料制备的气敏元件具有工作温度低、灵敏度高、响应速度快、稳定性好等优点.不需掺杂,改变工作温度和热处理温度便可获得对酒精蒸汽和C_2H_2气体具有选择性的气敏元件.这种材料像SnO_2,ZnO气敏材料一样,在205℃左右出现电导极值.超微粒α-Fe_2O_3的气敏机制属表面控制型.     

掺杂方式及掺杂量对α-Fe_2O_3敏感性能的影响

本文研究了用不同种类铁盐作原料,用共沉法制备α-Fe_2O_3粉体,在掺杂和不掺杂时的气敏特性。并进一步研究了掺杂方式对气敏特性的影响,解释了α-Fe_2O_3的初始电阻值、气体灵敏度随掺杂含量的变化关系,说明了SnO_2在α-Fe_2O_3气敏性中的作用。     

用PCVD制备的SnO2导电薄膜及其对NOx的气敏特性

本文利用PCVD方法制得了SnO_2导电薄膜,分析了其电学性能与沉积参数的关系,同时测得该膜具有负温阻特性,这种薄膜是n型半导体膜。在不同温度和不同NOx气体浓度下,对该膜进行了NOx气敏特性的测试。发现在常温下,SnO_2薄膜对NOx,具有较高的灵敏度,响应时间快的特性。     

SnO_2纳米结构气体传感器制备与气敏特性研究

由于二氧化锡(SnO_2)稳定的理化性质与优越的导电性能,制备的气体传感器具有灵敏度高、寿命长、稳定性好等特点。利用水热法制备了纳米结构SnO_2材料,进而制作旁热式气体传感器。通过调节氢氧化钠(Na OH)的量,研究不同浓度下纳米结构SnO_2材料的形貌,搭建实验平台,测试不同形貌下敏感材料的灵敏度、选择性、重复性,并分析其敏感机理。     

SnO2超微粒薄膜气敏元件的研制与测试

用射频磁控反应溅射法在Si基片上沉积SnO_2超微粒薄膜,溅射过程中适量掺Pd,用IC技术制成气敏元件.实验结果表明:该元件在90℃左右时对氢气有极高的灵敏度,是一种薄膜化、集成化、高选择性的气敏元件.本文介绍薄膜制备、微观结构分析、元件设计及气敏特性测试.     

掺Rh对纳米SnO2的气敏性能的影响

以无机试剂为前驱物,采用溶胶—凝胶法合成了纳米级 SnO_2,以此为基材掺入不同量 Rh 作为气敏材料制成气敏元件。测试了它们的阻温特性和气敏性能。通过比较它们对还原性气体的灵敏度和选择性,讨论了掺入 Rh 催化剂对纳米 SnO_2的阻温特性和气敏性能的影响。结果表明,纳米 SnO_2具有特征的阻温曲线。随着 Rh 催化剂掺入,不仅引起电阻增大,同时掺杂 Rh 占据表面活性位,使纳米 SnO_2对表面氧吸附时的物种类型相互转换的影响体现不出来。不过,在工作温度为300℃时。掺入0.2%Rh 催化剂使得纳米级 SnO_2对 C_2H_5OH 和 petrol、H_2的灵敏度提高了10倍以上,而且使其对 petrol 与 C_4H_(10)的选择性检测性提高了3倍以上,对 C_2H_5OH 与 CO 的选择性检测性提高2倍以上。     

半导体气敏元件在水果保鲜中的应用研究

以溶胶-凝胶法制备SnO_2和In_2O_3纳米晶粉体,以沉淀法制备WO_3粉体材料.经过掺杂及表面修饰技术研制出对低浓度乙烯、乙醇、H_2S有较高灵敏度、较好选择性和较快响应恢复特性的旁热式管式元件.用制得的三种元件对草莓和香蕉的存储过程进行测试,发现在水果存储过程中,各种气体在不同阶段释放的量是不同的,为水果的成熟度测试仪器的研究创造了条件.     

选择性CO气敏元件的研制

<正> 如何提高氧化物半导体气敏元件对CO气体检测的灵敏度、选择性和稳定性,开拓在工业和环境监测中的应用,一直是人们十分关注的问题,利用SnO_2、WO_2、ZnO等为基体材料和不同的工艺方式在做着广泛的研究,本文对以SnO_2为基体的CO选择性气敏元件的研制作了进一步的探讨。     

掺锆SnO_2陶瓷的乙醇气敏特性研究

在研究SnO_2乙醇气体敏感陶瓷中,比较添加物,发现ZrO_2对乙醇气体有较高的灵敏度。进而从工艺上研究了添加ZrO_2时的最佳烧结温度和预烧温度。分析了烧结温度与测试初始电阻的关系。总结出不同条件下乙醇的分解物不同。提出ZrO_2的催化机理是活化表面羟基,释放占有的电子,释放表面的吸附位,从而提高氧离子的效率。     

Microstructure control of TiO2 nanotubular films for improved VOC sensing

Porous gas sensing films composed of TiO₂ nanotubes were fabricated for the detection of volatile organic compounds (VOCs), such as alcohol and toluene. In order to control the microstructure of TiO₂ nanotubular films, ball-milling treatments were used to shorten the length of TiO₂ nanotubes and to improve the particle packing density of the films without destroying their tubular morphology and crystal structure. The ball-milling treatment successfully modified the porosity of the gas sensing films by inducing more intimate contacts between nanotubes, as confirmed by scanning electron microscopy (SEM) and mercury porosimetry. The sensor using nanotubes after the ball-milling treatment for 3 h exhibited an improved sensor response and selectivity to toluene (50 ppm) at the operating temperature of 500 °C. However, an extensive ball-milling treatment did not enhance the original sensor response, probably owing to a decrease in the porosity of the film. The results obtained indicated the importance of the microstructure control of sensing layers in terms of particle packing density and porosity for detecting large sized organic gas molecules.     

Effect of aluminium doping on structural and gas sensing properties of zinc oxide thin films deposited by spray pyrolysis

A facile spray pyrolysis route is used to deposit aluminium doped ZnO (AZO) thin films on to the glass substrates. It is observed that on aluminium doping the particle size of ZnO reduces significantly; moreover, uniformity of particle also gets enhanced. Their XRD study reveals that intensity ratio of crystal planes depend on the aluminium doping concentration. The gas response studies of; ∼800 nm thick Al-doped ZnO films at different operating temperatures show that 5 at% Al-doped ZnO thin film exhibits highest response towards H₂S gas at 200 °C. The results suggest that the gas response strongly depends on the particle size and aluminium doping in the ZnO.     

电场对二氧化锡纳米薄膜电性质 和气敏性质的影响

本文研究了用直流气体放电活化的反应蒸发制备的二化锡纳米薄膜的表面性质、电学性质以及气敏性质，重点研究正反向电场对其电学性质和气敏性质的影响，从理论上探讨了它的气敏机理。     

电场对SnO_2/ZnO UPF的电性质及气敏性质的影响

研究了用直流气体放电活化反应蒸发沉积法技术制备的超微粒子复合薄膜的电学性质及气敏性质，并对其作用机理进行了分析解释．     

Growth of tin oxide thick films by plasma spray physical vapor deposition

Tin oxide thick films were deposited by plasma spray physical vapor deposition at various oxygen flow rates and raw powder feeding rates. The films are fundamentally porous and the deposition rates reach 60 μm/min at highest under the present condition. Local structures are however modified with the deposition condition. For example, relatively uniform columnar structure formed at high oxygen flow rate, whereas granular grains were observed when no oxygen gas was introduced. In contrast, granulate films were deposited at high powder feeding rate while rather uniform columnar films formed at low feeding rate. The gas sensors fabricated with these PS-PVD films have exhibited high sensitivity against formaldehyde gas at concentration as low as 100 ppb, which characterizes the sensors prepared by the PS-PVD method. Such sensitivities are found to change with the film microstructures that are in turn controlled by the PS-PVD conditions.     

基体对SnO_2 UPF成膜结构的影响

对不同基体上采用直流气体放电活化反应蒸发沉积法（ＤＣ－ＧＤＡＲＥ）制备的氧化锡超微粒薄膜的晶相结构进行了分析。结果表明：不同的基体对此类薄膜的生长有极重要的影响作用。     

超微粒锌、锡氧化物薄膜的阻温特性

报道了锌、锡氧化物超微粒子薄膜的阻温特性，并根据氧表面吸附模型和截流子穿越势垒理论对其结果加以解释。     

外磁场诱导Ni-ZnO型甲醛传感器气敏性研究

结合NiO和四针状纳米ZnO的优点,提出了利用平行和垂直气敏膜的磁场诱导Ni纳米颗粒在四针状纳米ZnO气敏膜中的分布来制备甲醛气体传感器的方法.介绍了制备方法,分析了对甲醛的敏感性及其气敏性机理,测试了在不同使用方式中的稳定性.实验结果表明:平行于厚膜表面的磁诱导5%的Ni掺杂ZnO厚膜具有较好的稳定性,同时,对甲醛具有最佳的气敏性和检测的重复性,以其作为甲醛气体探测器具有很好的前景.     

Influence of pH on particle size and sensing response of chemically synthesized chromium oxide nanoparticles to alcohols

Nanoparticles of chromium oxide have been synthesized by following a co-precipitation route at various pH values of the precursor solution. Structural and morphological analysis were carried out by using XRD and TEM techniques which revealed that the size of nanoparticles synthesized at pH 9 was smaller as compared to those synthesized at other pH values. The thick films of synthesized samples were deposited on alumina substrate and their sensing response to methanol, ethanol and isopropanol was investigated at different operating temperatures. It was observed that all the sensors gave optimum response at 250 °C. It has been observed that sample prepared at pH 9, being a collection of smallest particles as compared to other samples, exhibited high sensing response to alcohol vapour. Sensor response of all the samples tested was significantly higher towards isopropanol vapour than towards methanol or ethanol.In the present study the effect of particle size on intergranular activation energy has been studied as well. It was found that smaller particles possess high activation energy and exhibit higher sensing response as compared to that of larger particles. This type of study may help in the selection of particle suitable for gas sensing.     

A comparative study of the physical properties of CdS, Bi2S3 and composite CdS–Bi2S3 thin films for photosensor application

Thin films of CdS, Bi₂S₃ and composite CdS–Bi₂S₃ have been deposited using modified chemical bath deposition (M-CBD) technique. The various preparative parameters were optimized to obtain good quality thin films. The as-deposited films of CdS, Bi₂S₃ and composite were annealed in Ar gas at 573 K for 1 h. A comparative study was made for as-deposited and annealed CdS, Bi₂S₃ and composite thin films. Annealing showed no change in crystal structure of these as-deposited films. However, an enhancement in grain size was observed by AFM studies. In addition change in band gap with annealing was seen. A study of spectral response, photosensitivity showed that the films can be used as a photosensor.