掺Pt的SnO2薄膜气敏特性研究

用直流磁控溅射法分别在si（111）基片及陶瓷基片上制备掺有Pt的Sn02薄膜,并进行500℃～700℃退火处理,对掺杂前后的薄膜进行XRD分析,测试各掺杂样品气敏特性。500℃退火后,掺杂样品对各种有机气体有较高的灵敏度,随着溅射时间的延长,气敏特性提高。700℃退火后,45min溅射的样品对氨气有很高的灵敏度和很好的选择性,最佳工作温度为220℃左右。随着掺杂时间延长,气敏特性降低。     

钼掺杂降低TiO2氧敏薄膜最佳工作温度研究

用直流反应磁控溅射法在陶瓷基片上制备出TiO2薄膜.并进行1100℃,2h的退火处理.配置钼酸铵溶液,利用浸渍法处理TiO2薄膜若干时间.取出后,进行500℃,3h退火处理.用气敏测试箱对制备出的TiO2薄膜的氧敏特性进行试验测试,发现对氧气有很好的敏感特性,比未经此项工艺处理的TiO2薄膜的最佳工作温度降低100℃,为300℃左右,并进行SEM测试,分析其表面结构,研究气敏机理.     

TiO2薄膜制备及其气敏特性

NO2是一种强毒性气体,本文利用了溶胶一凝胶法在硅片及陶瓷管上制备TiO2纳米薄膜,并探讨了在制备过程中不同的因素对薄膜成膜质量的影响。并用马弗炉对硅片及陶瓷管上制备的TiO2纳米薄膜进行不同温度的退火处理。对其分别进行XRD的分析,和原子力显微镜分析。利用气敏测试系统对不同的退火温度下的气敏元件进行测试。研制出工作温度低,气敏特性强,响应恢复特性好的基于TiO2的NO2气敏传感器。     

一种便携式TiO2薄膜乙醇气敏传感器的研制

研制了一种适合于乙醇检测的新型TiO2基薄膜气敏传感器.敏感材料是采用直流磁控反应溅射法制备在Al2O3陶瓷管上的TiO2薄膜,薄膜经过退火处理(500℃、3 h)后,得到对乙醇蒸汽具有很好选择性和灵敏度的锐钛矿相TiO2,其最佳工作温度为270℃左右,响应时间2 s,恢复时间3 s.测量电路采用以ARM7为核的LPC2131微控制器实时监测电源电压,自动调整占空比,从而实现对加热温度的精确控制.通过测量敏感薄膜的电阻,并与乙醇气体浓度进行校准,最终显示被测气体的浓度.整个传感器采用低功耗设计,具备报警功能,同时提供了一个友好的用户界面.     

直流反应磁控溅射法制备WO_3薄膜及其氢敏特性研究

采用直流反应磁控溅射法,在未抛光的A l2O3基片上制备WO3薄膜,在干燥空气中经过热处理;利用SEM观察薄膜表面形貌;通过XRD测量,对薄膜的晶体结构进行分析;薄膜氢敏特性测试采用静态配气法。经过400℃热处理,当工作温度在270℃时,对体积分数为3×10-4氢气的灵敏度达到了77,稳定性较高,选择性好,响应时间很快,在15 s以内,是一种较理想的氢敏材料。     

三氧化钨纳米薄膜制备与气敏性能的研究

讨论一种对二氧化氮具有高灵敏性的WO3纳米薄膜的制备方法.当基片温度为室温,溅射混合气体(O2/Ar)的比例为1:1时,用直流反应磁控溅射法制备的薄膜,经过两步热处理(300℃/600℃),得到纳米结构WO3气敏元件.通过XRD、XPS和SEM对该薄膜的晶体结构和化学成分进行分析,用静态配气法测试NO2气敏特性.在Si3N4基片上制备的这种薄膜对空气中较低浓度的NO2(体积分数为0.1×10-5～3×10-5)具有优异的敏感特性和响应特性,最佳工作温度为150℃,在此温度下对其他一些气体(如CO,C2H5OH,NH3)的敏感性很差,显示出良好的选择性.     

溅射Au对SnO_2/Fe_2O_3薄膜气敏特性的影响

通过直流溅射Au对PCVD方法制备的SnO2/Fe2O3双层薄膜的SnO2表面进行了修饰,并对修饰后的Au SnO2/Fe2O3薄膜的气敏特性进行了观测。结果表明,Au的催化作用使Au SnO2/Fe2O3薄膜气敏器件对CO,H2,C2H5OH等气体的灵敏度增大2～3倍,相应于最大灵敏度的工作温度均降低约60℃。这显示直流溅射Au是改善SnO2/Fe2O3双层薄膜气敏性能的一种有效手段。     

直流反应磁控溅射WO3薄膜气敏特性研究

用直流反应磁控溅射法制成纳米结构的WO3薄膜气敏传感器,通过XRD,SEM和XPS对该薄膜的晶体结构和化学成分进行分析,研究了不同基片上制备的WO3薄膜的氨敏特性与薄膜厚度、退火温度的关系.实验得到的薄膜粒径大小约30-50 nm,结果表明:在未抛光的三氧化二铝基片上沉积厚度为40 nm的WO3薄膜,经过400℃退火,在体积分数为5×10-5 NH3中的灵敏度达到300,而且气体选择性好,响应-恢复时间短,可以作为理想的氨敏元件.     

Pr6O11/SnO2复合材料的制备及对异丙醇气敏特性的研究

通过水热法和退火处理制备了不同Pr浓度(0%,1%,2%,4%)的Pr6O11/SnO2复合材料。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等方法对制备材料的物相结构、微观形貌和元素组成进行了表征,并制成旁热式气敏元件,对异丙醇气体进行气敏测试。实验结果表明,基于2%样品的Pr6O11/SnO2气体传感器的气敏性能最佳,在最佳工作温度200℃下对100×10^-6异丙醇气体响应达到16.2,是纯相SnO2传感器响应的2.3倍。最后,对基于Pr6O11/SnO2复合材料气体传感器的气敏机理进行了分析讨论。     

PdO修饰的SnO2纳米球的制备及其气敏特性研究

通过溶剂热法和退火处理制备了不同浓度(0 mol％,2 mol％,5 mol％,10 mol％)PdO修饰的SnO2纳米球.采用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)等测试手段对材料的物相、元素种类和形貌进行了表征,并制成气敏元件,对氢气(H2)进行气敏测试.实验结果表明:5 mol％PdO修饰的SnO2纳米球气体传感器最佳工作温度为175℃,其对100×10-6氢气灵敏度达到19,是纯的SnO2纳米球的灵敏度的3倍.最后,对PdO修饰氧化锡纳米球气体传感器气敏机理进行了分析讨论.     

High sensitivity ethanol gas sensor integrated with a solid-state heater and thermal isolation improvement structure for legal drink-drive limit detecting

The paper reports the successful fabrication of ethanol gas sensors with tin-dioxide (SnO₂) thin films integrated with a solid-state heater, which is realized with technologies of micro-electro-mechanical systems (MEMS), and are compatible with VLSI processes. The main sensing part with dimensions of 450×400 μm² in this developed device is composed of a sensing SnO₂ film, which is fabricated by electron-gun evaporation with proper annealing in ambient oxygen gas to yield fine particles and good structure. An integrated solid-state heater with a 4.5 μm-thick cantilever bridge (1000×500 μm²) structure is made of silicon carbide (SiC) material by MEMS technologies. The sensitivity for 1000 ppm ethanol gas reaches as high as 90 with 10 s and 2 min for the response and recovery time, respectively, at an operating temperature of 300°C. Those experimental results also exhibit a much superior performance to that of a popular commercial ethanol gas sensor TGS-822. Therefore, the developed sensor with high performance is a good candidate for some specific application in automobile to detect drink-drive limit and allows an array integration available with various films for controlling each element at separate resistance.     

纳米WO_3薄膜的光学性质及氢敏特性研究

采用磁控直流溅射法制备出纳米WO3薄膜,在N2气中进行退火处理。采用分光光度计、XRD等对退火前后的WO3薄膜进行了光学特性的分析。研究表明:在623 K进行退火处理的薄膜均匀、致密,呈现出较好的结晶态。采用光源激发对纯WO3薄膜在不同温度条件下的氢敏特性进行了研究,实验显示:WO3薄膜对H2的敏感性与温度有关,在348 K温度条件下,WO3薄膜的氢敏效应最好。     

Effect of annealing and temperature on the NO2 sensing properties of tellurium based films

Influences of temperature and annealing on the electrical and sensing properties toward NO₂ of tellurium based films were investigated. The annealing at temperatures more than 100 °C causes a sharp decrease both of electrical resistance and sensitivity of the films. SEM analyzes indicated that annealing induced structural evolution of the films, including growth of large crystals in the matrix. Temperature-dependent electrical conductivity is strongly affected by presence of an NO₂ environment. The sensitivity toward NO₂, being controlled by gas concentration, decreases with operating temperature increase. On the other hand, the increase of operating temperature leads to a reduction of response–recovery times.

The results are discussed taking into consideration the contributions of grain boundary as well as grain bulk and surface resistance to the total conductivity. It is assumed the surface, including grain boundary, hole-enriched region is formed as a result of dangling bond chalcogen’s lone-pair electron interaction. Chemisorption of NO₂ molecules is accompanied by hole enrichment of the surface and grain boundary region, due to interaction of these molecules with lone-pair electrons.     

La掺杂ZnO和SnO2薄膜的气敏特性

真空蒸发沉积薄膜再经热氧化获得n型掺La的ZnO和SnO2薄膜(玻璃衬底)研究掺La含量与热氧化工艺对薄膜的物相结构、表面形貌和气敏特性的影响.实验给出:掺La使薄膜表面颗粒细化,随La含量增加,ZnO,SnO2薄膜平均晶粒尺寸均增大.掺La可明显降低2种薄膜的气敏工作温度相比之下,掺La对ZnO薄膜的灵敏度改善明显优...     

Temperature dependent H2S and Cl2 sensing selectivity of Cr2O3 thin films

The conductometric gas sensing characteristics of Cr₂O₃ thin films - prepared by electron-beam deposition of Cr films on quartz substrate followed by oxygen annealing - have been investigated for a host of gases (CH₄, CO, NO₂, Cl₂, NH₃ and H₂S) as a function of operating temperature (between 30 and 300 °C) and gas concentration (1-30 ppm). We demonstrate that these films are highly selective to H₂S at an operating temperature of 100 °C, while at 220 °C the films become selective to Cl₂. This result has been explained on the basis of depletion of chemisorbed oxygen from the surface of films due to temperature and/or interaction with Cl₂/H₂S, which is supported experimentally by carrying out the work function measurements using Kelvin probe method. The temperature dependent selectivity of Cr₂O₃ thin films provides a flexibility to use same film for the sensing of Cl₂ as well as H₂S.     

稀土Nd掺杂纳米ZnO薄膜气敏特性

研究了用真空气相沉积法在玻璃衬底上制备掺稀土Nd的ZnO薄膜的气敏特性,实验给出,经温度为500℃,时间为45min的氧化、热处理的掺Nd的ZnO薄膜的晶粒尺寸、结构特性均发生变化。随掺Nd质量分数的增大,薄膜的晶粒尺寸从53nm减小至20nm。经掺Nd(质量分数为4.96×10-2)后纳米ZnO薄膜对乙醇气体的选择性和灵敏性均得到明显的改善。在1.5×10-3体积分数的乙醇气体中最高灵敏度为34,相应的薄膜工作温度为200℃。     

氧化锌气体传感器的制备及甲烷检测特性研究

甲烷(CH4)是电力变压器油纸绝缘中溶解的主要故障特征气体,能有效反映运行变压器油纸绝缘故障.气体传感检测是油中气体在线监测、分析的关键.基于水热法,制备了氧化锌(ZnO)纳米片和纳米球气敏材料及传感元件,基于实验室搭建的微量气体检测平台测试了其对CH4的检测特性.研究表明:基于ZnO纳米片制作的气体传感器比纳米球传感器对CH4表现出更好的气敏性能,对50μL/L CH4的最佳工作温度降低了约60℃,同时对低浓度(1μL/L～20μL/L)CH4表现出较高的线性度和长期稳定性.本研究对研制高性能的ZnO基CH4气体传感器奠定了基础.