Properties of Indium-Doped ZnO Films Prepared in an Oxygen-Rich Plasma

Indium-doped zinc oxide (ZnO:In) films were prepared in an Ar:O₂ plasma by reactive magnetron sputtering. The x-ray diffraction (XRD) patterns presented the crystal structures of ZnO:In films, while transmission spectra and photoluminescence (PL) spectra showed the changed band gap and the visible emission from defects, as compared to the PL spectra of undoped ZnO films. It was concluded that the increase of substrate temperature enhanced the crystal quality of ZnO:In films; the incorporation of In made the c-axis constant of the samples larger than that of undoped ZnO films; the blue emission was due to the transition from an unknown donor level by indium doping to the valance band; and the orange-green emission originated from acceptor defects (O_Zn) formed in the O-rich plasma. Meanwhile, the current- voltage characteristics and persistent photoconductivity phenomenon also could be explained by the increased acceptor defects (O_Zn) that formed when the substrate temperature was increased.     

掺TiO2的ZnO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TiO2的ZnO薄膜,并进行500℃、700℃退火处理,对掺杂前后ZnO薄膜进行XRD分析,测试各掺杂样品气敏特性.500℃退火后,各掺杂样品对有机气体有较高的灵敏度,随着掺杂时间延长,气敏特性提高.700℃退火后,2 min掺杂的样品对乙醇有很高的灵敏度和很好的选择性,最佳工作温度为220℃左右.而其他掺杂量的样品对乙醇气体灵敏度低,随着掺杂时间延长,气敏特性降低.     

Highly Conducting Transparent Indium-Doped Zinc Oxide Thin Films

Highly conducting transparent indium-doped zinc oxide (IZO) thin films have been achieved by controlling different growth parameters using radio frequency magnetron sputtering. The structural, electrical, and optical properties of the IZO thin films have been investigated for varied indium content and growth temperature (T _G) in order to find out the optimum level of doping to achieve the highest conducting transparent IZO thin films. The highest mobility and carrier concentration of 11.5 cm²/V-s and 3.26 × 10²⁰ cm^?3, respectively, have been achieved in IZO doped with 2% indium. It has been shown that as T _G of the 2% IZO thin films increase, more and more indium atoms are substituted into Zn sites leading to shift in (002) peaks towards higher angles which correspond to releasing the stress within the IZO thin film. The minimum resistivity of 5.3 × 10^?4 Ω-cm has been achieved in 2% indium-doped IZO grown at 700°C.     

Nanostructured ZnO Films for Room Temperature Ammonia Sensing

Zinc oxide (ZnO) thin films have been deposited by a reactive dc magnetron sputtering technique onto a thoroughly cleaned glass substrate at room temperature. X-ray diffraction revealed that the deposited film was polycrystalline in nature. The field emission scanning electron micrograph (FE-SEM) showed the uniform formation of a rugby ball-shaped ZnO nanostructure. Energy dispersive x-ray analysis (EDX) confirmed that the film was stoichiometric and the direct band gap of the film, determined using UV–Vis spectroscopy, was 3.29 eV. The ZnO nanostructured film exhibited better sensing towards ammonia (NH₃) at room temperature (～30°C). The fabricated ZnO film based sensor was capable of detecting NH₃ at as low as 5 ppm, and its parameters, such as response, selectivity, stability, and response/recovery time, were also investigated.     

Enhancement of Oxidation Resistance and Electrical Properties of Indium-Doped Copper Thin Films

Copper thin films with high conductivity and good resistance to electromigration can be used in advanced electronic devices. However, the poor corrosion resistance of copper must be overcome. This work elucidates the possibility of using a self-forming passivation layer to prevent copper oxidation in lightly indium-doped copper thin films deposited directly on glass substrates and annealed under various oxygen atmospheres. The resistivity of the studied film declined gradually as the film was annealed at an elevated temperature because of the grain growth of the Cu film and the precipitation of indium from the In-doped Cu thin film, as revealed by X-ray diffraction, four-point probe measurements, and transmission electron microscopy. A copper film with high indium content exhibited superior passivation when the film was annealed in an oxygen-rich ambient, but it exhibited high resistivity because of its high indium content. The electrical and passivation properties demonstrated that indium is a promising alloying element for use in copper films for future metallization structures and thin-film transistors.     

水热因素对ZnO纳米材料气敏性能的影响

通过水热法合成了不同形貌的氧化锌(ZnO)气敏传感材料,利用X射线衍射仪和热场发射扫描电子显微镜对其进行了结构表征和分析,研究了不同的水热因素对其形貌的影响。利用Agilent B2900A quick I/V测试软件测试了其对乙醇气体的敏感性。实验结果表明:前驱体浓度、反应时间和反应温度会对ZnO纳米棒的生长造成显著影响。在前驱体浓度为20 mmol/L、反应时间为8 h、反应温度为95℃的条件下进行水热反应能得到较高质量和良好长径比的纳米线。通过气敏性能测试发现该条件下制备的样品在使用叉指电极时响应度为79%,响应时间和恢复时间均为4 s,表明该条件下制备出的气敏传感材料具有良好的响应度、响应时间和恢复时间。     

ZnO纳微分级结构的形貌调控及其气敏性能

采用水热法,通过调控反应温度得到了具有不同微观形貌的ZnO纳微分级结构。扫描电子显微镜(SEM)结果表明,纳微分级结构分别由纳米棒或纳米片按不同方式堆积而成。X射线衍射(XRD)结果表明,所制备的ZnO纳微分级结构均为纤锌矿结构。此外,通过BET比表面积测试与气敏性能测试发现,微观形貌不同的分级结构具有不同的比表面积、孔隙率和平均孔径,同时气敏性能也有差异。在反应温度为65、100和150℃下制备了样品S_1、S_2和S_3。相比另外两组样品,纳米片堆积而成的样品S_2具有更大的比表面积(4.87 m~2/g)、更高孔隙率(0.092 6 cm~3/g)和更大平均孔径(76 nm),其最佳测试温度为300℃,在三个样品中最低(S_1的最佳检测温度为370℃,S_3的最佳检测温度为394℃)。同时在最佳检测温度下S_2对气体响应值最高(110),响应时间最短(7.10 s)。由此说明,高比表面积和孔隙率有利于气体的扩散,从而能够提高材料的气敏性能。     

Solution growth of Indium-Doped silicon

Indium-doped silicon has been grown from indium-rich solutions using a gradient-transport solution growth process. The growth temperatures were varied from 950‡ to 1300‡C to determine the solubility limits of indium in silicon. The maximum indium concentration obtained was 1.6×10¹⁸/cm³ at a growth temperature of 1300‡ but indications are that the maximum solubility is 2. 5×10¹⁸/cm³. The growth process is described by one-dimensional diffusion limited transport and predicts growth rates in excess of lcm/day at 1300‡C. Infrared absorption measurements were used to monitor the indium, oxygen and carbon concentrations, in addition to the shallower .indium: X defect found in the crystals. The solution-grown crystals were found to have a lower concentration of this shallower defect than melt grown crystals of the same indium concentration. The oxygen and carbon concentrations increased with the increased growth temperatures suggesting a solubility limited value. The shallower indium: X defect also increased with growth temperature, but the concentration was significantly lower than typically found in melt-grown crystals. The peak optical cross-section for indium was also determined to be 5.3×10^-17cm² from these measurements. This work was sponsored in part by the Defense Advanced Research Projects Agency under Order No. 3211, monitored by NV & EOL under Contract No. DAAK70-77-C-0194.     

基于ZnO纳米结构的H2、NH3气体敏感性研究

通过简单的水热法在金电极上刺备了氧化锌纳米棒,从而制成了气体传感器。研究了氧化锌纳米棒的结构和特性,发现用该材料制成的气体传感器时于500ppm的NH3和H2在150℃下有较灵敏的反应,并探讨了产生传感效应的机理。该传感器制备方法简单、廉价、环保,适合大批量生产,有望应用于工业生产和日常生活的气体探测。     

Influence of Surface Roughness on the Lasing Performance of Highly Disordered ZnO Films

The influence of surface roughness on the lasing performance of highly disordered ZnO films is studied. It is found that the highly disordered ZnO films with improvement in surface quality by ion-beam milling can significantly reduce the corresponding scattering loss as well as increase the slope efficiency of the light-light curves even with the presence of MgO cladding layer. Furthermore, it is noted that random lasing action is less dependent on the surface roughness of the ZnO films     

磁控溅射法制备SnO2-CuO薄膜及其气敏特性研究

用直流磁控溅射法分别在Si及陶瓷管上制备掺有CuO的SnO2纳米薄膜,并用马弗炉进行500 ℃和700 ℃的退火处理.利用气敏测试系统对各样品进行气敏特性测试,500 ℃退火的样品对几种被测气体基本都有较高的灵敏度,且随着工作温度的提升,气敏特性下降.700 ℃退火的样品对乙醇具有很好的选择性,表现较好的灵敏度,当最佳工作电压为6.5 V时,在乙醇气体小注入条件下,对样品的测试体现了样品良好的气敏特性.     

热氧化法制备ZnO薄膜及其紫外探测特性研究

采用电子束蒸发方法在玻璃衬底上沉积了Zn薄膜,然后在空气中进行了400 ℃至550 ℃加热退火处理,并基于金属-半导体-金属(MSM)平面式结构,制备了ZnO光电导型紫外探测器.实验发现:退火后的薄膜样品表面出现了ZnO纳米线,纵横比在300～1000间;探测器的响应峰值波长约为360 nm,紫外区光响应度是可见区的5倍以上;360 nm紫外光照射的瞬态响应符合e指数变化规律,e指数曲线拟合所得到的驰豫时间常数反映了这个过程中的时间积累.     

基于电纺纤维的CuO/SnO_2薄膜及其气敏特性

研究了一种基于静电纺丝纳米纤维制备异质结薄膜的方法。采用静电纺丝技术在硅衬底上依次沉积PVP/CuCl2.2H2O和PVP/SnCl4.5H2O纳米纤维,经过氧等离子体刻蚀并高温退火处理后得到了基于多孔纳米纤维的CuO/SnO2异质结薄膜。利用扫描电子显微镜(SEM)和X射线衍射技术(XRD)对纤维的形貌和结晶状态进行了表征。电学特性及气敏特性测试结果表明,该异质结薄膜具有明显的整流特性,在100℃的工作温度下,对H2S气体响应和恢复速度快、检测限低、选择性好。     

ZnO薄膜及ZnO-TFT的性能研究

采用MOCVD法在SiNx绝缘薄膜上生长了ZnO薄膜,通过X射线衍射与光致发光光谱表征了ZnO薄膜的质量.其结果是:XRD特征峰半高全宽0.176°,光致发光仅有381.1nm的发光峰,展现了ZnO薄膜光电特性的优势.制备了底栅型ZnO薄膜晶体管,测试表明器件具有明显的场效应特性及饱和特性.     

多层结构氧化锌薄膜制备

介绍了高频声体波微波延迟线用多层结构氧化锌薄膜的制作方法，并对这种交替排列不同结晶取向的多层氧化锌薄膜的微观结构、成膜机理进行了分析和阐述。用具有不同机电耦合系数、厚度为半波长的交替排列多层氧化锌薄膜制成了中心频率为８ＧＨｚ的声体波微波延迟线。同时亦给出了这种新结构的氧化锌压电材料的生长条件及相应的实验结果     

氩气压强对溅射法制备Ga掺杂ZnO薄膜性能的影响

采用射频磁控溅射法在玻璃衬底上制备了高质量的Ga掺杂ZnO透明导电薄膜(GZO).通过X射线衍射、原子力显微镜、四探针电导率测试仪等表征方法研究了溅射气压对薄膜结晶特性及导电性能的影响.所制备的GZO薄膜是具有六角纤锌矿结构的多晶薄膜,最佳择优取向为(002)方向.随着溅射气压的增大,薄膜方块电阻与薄膜电阻率均随之增大.最小方块电阻可达17.6 Ω/□,最小薄膜电阻率为7.3×10~(-4) Ω·cm.另外,GZO薄膜在可见光范围内的透过率达到了90%以上.     

V掺杂ZnO中空微笼结构的制备及其对H_2S检测气敏性能

采用溶剂热法制备了纯ZnO与V掺杂ZnO中空微笼结构,利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和X射线能量色散谱(EDS)对其微观形貌和晶体结构进行表征,发现由纳米颗粒组成的菱形十二面体V掺杂ZnO中空多孔结构在掺杂V后有V_2O_5晶体生成。进一步制备了基于纯ZnO与V掺杂ZnO中空微笼结构的气体传感器,并研究了传感器对H_2S的气敏特性。测试结果表明,基于V掺杂ZnO中空微笼结构的传感器对体积分数为5×10~(-6)的H_2S的响应值达到90.2,气敏性能更加优异。而且该传感器在100℃的最佳工作温度下,具有体积分数2×10~(-7)～1×10~(-5)的良好线性动态区间和优异的选择性,并实现了在300℃的快速恢复。最后,分析了V掺杂ZnO中空微笼结构的气敏性能增强机理。     

低温沉积ZnO薄膜的压敏特性及其热处理影响

采用GDARE法在较低温度下,通过一次和多次沉积制备单层及多层ZnO薄膜.AFM和XRD分析表明,薄膜具有以ZnO(002)晶面取向为主的多晶结构,多层膜的晶粒尺寸增大.经200～300℃退火热处理,薄膜呈现出良好的低压压敏特性.经200℃退火热处理后,多层ZnO薄膜的非线性系数达到61.54,压敏电压20.10V.在一定范围内升高热处理温度,可明显降低压敏电压.分析了不同膜层及热处理温度对ZnO薄膜压敏特性的影响机理.     

低温沉积ZnO薄膜的压敏特性及其热处理影响

采用GDARE法在较低温度下,通过一次和多次沉积制备单层及多层ZnO薄膜.AFM和XRD分析表明,薄膜具有以ZnO(002)晶面取向为主的多晶结构,多层膜的晶粒尺寸增大.经200～300℃退火热处理,薄膜呈现出良好的低压压敏特性.经200℃退火热处理后,多层ZnO薄膜的非线性系数达到61.54,压敏电压20.10V.在一定范围内升高热处理温度,可明显降低压敏电压.分析了不同膜层及热处理温度对ZnO薄膜压敏特性的影响机理.