磁控溅射制备AlN过渡层ZnO薄膜及其性能研究

大量研究表明ZnO薄膜已在气敏器件、表面声波器件和压敏器件等方面得到较为广泛的应用。由于Si与ZnO的晶格常数及热膨胀系数的失配度均很大,难以实现高质量ZnO薄膜的外延生长,采用中间缓冲层是一种值得研究的工艺。由于AIN的晶格结构与ZnO相同,所以可作为生长高质量ZnO薄膜的缓冲层,并改善ZnO/AlN界面结构。实验采用射频磁控溅射制备了ZnO/AlN双层膜,研究了薄膜的结构和形貌。结果表明,相比于相同工艺下制备的ZnO/Si薄膜,双层膜的生长取向依然是(002),应力减小,结晶质量更好。     

研究氧化锌纳米材料的研究进展

很多人近年来对ZnO纳米材料进行了广泛的研究。本文主要从光学、气敏以及材料的形貌三个方面综述了ZnO纳米材料的进展。通过大量的掺杂不同的元素和改变制备条件的实验,观察ZnO纳米材料的发光、气敏和形貌改变,进而推测出ZnO纳米材料的发光、气敏和形貌改变的机理。     

Dy3+和La3+掺杂ZnO薄膜的特点及其气敏传感特性

采用真空蒸发的方法制备了掺杂原子比为3%、5%和9%的La掺杂和Dy掺杂的ZnO薄膜.用扫描电子显微镜(SEM)、X射线衍射(XRD)谱和X射线光电子能谱(XPS)表征了所制得的ZnO薄膜的特性.发现所有薄膜都沿C轴取向优先生长.在对ZnO薄膜气敏特性的测量中,在低温条件下掺杂ZnO薄膜的电阻比非掺杂ZnO薄膜的小,且对乙醇和丙酮的灵敏度显著增强,且其中Dy掺杂的ZnO薄膜的气敏特性较La掺杂的ZnO薄膜为高.而空气中暴露9个月后的薄膜的气敏特性表明掺杂ZnO薄膜具有很好的稳定性.同时讨论了气敏传感机制和掺杂行为对薄膜灵敏度的影响.     

单分散Au/ZnO纳米球的可控制备及气敏性能研究

以二水合醋酸锌和二甘醇为原料,采用微波法制备ZnO单分散纳米球;采用柠檬酸还原法制备Au纳米颗粒,并通过静电作用将金纳米颗粒修饰在ZnO纳米球上制备Au/ZnO气敏材料.XRD结果证明了多晶ZnO的形成以及金属Au的成功修饰;FESEM和TEM观察到ZnO单分散纳米球由纳米颗粒组装而成,粒径约280nm;PL光谱对合成材料的晶体缺陷进行了提取,在此基础上深入讨论了Au/ZnO的增敏机理.气敏测试结果显示,Au/ZnO纳米球比未修饰的ZnO纳米球对丙酮具有更好的选择性与更低的检测温度,在体积分数为1×10-6下仍具有较强的气敏响应.     

ZnO/TiO_2分级纳米结构的制备及气敏性能

采用静电纺丝法和水热法制备了ZnO/TiO_2分级纳米结构,利用扫描电子显微镜和X射线衍射仪对材料的表面形貌和晶体结构进行了表征,并研究了ZnO/TiO_2分级纳米结构传感器的气敏特性.结果表明,ZnO/TiO_2分级纳米结构是ZnO纳米锥柱阵列均匀生长在TiO_2纳米纤维的表面,且水热法生长ZnO纳米锥柱阵列的过程未改变TiO_2纳米纤维的晶体结构.与ZnO纳米锥柱和TiO_2纳米纤维气敏元件相比,ZnO/TiO_2分级纳米结构气敏元件具有更高的灵敏度,且对丙酮具有较好的选择性.     

通过表面修饰提高ZnO纳米棒的气敏选择性与灵敏度

对化学水浴法制备的六方纤锌矿ZnO纳米棒,分别采用Ag、NiO以及CuO纳米颗粒进行了表面修饰处理,研究了表面修饰对ZnO纳米棒的气敏选择性、敏感性的作用.结果表明,经过表面修饰的ZnO纳米棒的气敏综合性能有了显著的改善,不仅材料的灵敏度得到了明显提高,而且,CuO修饰的ZnO纳米棒对硫化氢气体有很高的选择性.     

ZnO/SnO_2双层薄膜型气敏传感器

将纯的ZnO及SnO_2采用等离子溅射法制成ZnO/SnO_2双层膜,用XPS,SEM,XRD等手段对薄膜进行了分析测试。比较了单层SnO_2及ZnO薄膜与双层ZnO/SnO_2膜的气敏性质,发现双层膜较单层膜在灵敏度及选择性上都有所提高。简单讨论了元件的气敏机制。     

Au在ZnO极性面上吸附催化的第一性原理研究

ZnO作为一种压电、光电特性相结合的功能材料,有着极为广泛的用途.其禁带宽度对应于紫外光的波长，有望开发出应用于蓝光,蓝绿光,紫外光等多种发光器件.ZnO的激子结合能高达60 meV,远远高出GaN(21 meV),产生室温短波长发光的条件更加优越.     

掺杂ZnO气敏特性的研究进展

ZnO是一种新型的、性能优良的半导体材料。本文介绍了ZnO的制备和掺杂研究进展及其气敏机理,并指出了今后的发展趋势。     

Au/ZnO多孔纳米片及其紫外光照射下的NO_2气敏性能

采用水热法结合后期热处理技术制备了Au/ZnO多孔纳米片,并对其气敏性能进行了详细研究。Au/ZnO样品是由厚度约一二十纳米的多孔纳米片组成;气敏性能测试发现,在紫外光照射下Au/ZnO多孔纳米片结构对NO_2气体具有室温响应,检测限为100ppb。Au/ZnO传感器对100ppb NO_2气体的响应时间是21.5s,恢复时间是7s,灵敏度是1.25。当NO_2气体浓度增加到50ppm时,Au/ZnO传感器的灵敏度增加到138.3,是纯ZnO传感器的2.9倍。分析认为,Au/ZnO优异的室温气敏性能是由于在紫外光照射下材料内部产生光生电子-空穴对以及Au颗粒的催化作用。本论文为高性能、低功耗室温气体传感器的构筑提供了一种简易的方法。     

氩对四针状氧化锌场发射性能的影响

氧化锌是一种宽带半导体材料,由于其具有负电子亲和势,高的机械强度和良好的化学稳定性等特性,也被认为是一种很有发展潜力的场发射阴极材料。但是由于阴极材料在纳米量级,纳米材料的一些效应使其对工作的环境气体非常敏感。氩是采用薄膜型吸气剂的电真空器件中常见的残余气体成份。采用充气实验法研究了氩对氧化锌场发射的影响,得出其对氧化锌的场发射电流具有增强作用。由于氩的引入在一定程度上对系统起到了清洗的作用,系统内对氧化锌具有衰减作用的气体减少从而使得氧化锌发射电流在相同外加电压下增加。     

纳米氧化锌制备及应用研究进展

纳米氧化锌是具有优良性质的宽带隙半导体,在紫外光发射器件,透明导电材料,压电材料,气敏材料,太阳能电池等方面有着广泛应用。综述了纳米氧化锌最新的制备方法及应用的研究进展,提出了对以后研究的展望。     

Enhanced deposition of ZnO films by Li doping using radio frequency reactive magnetron sputtering

Radio frequency (RF) reactive magnetron sputtering was utilized to deposit Li-doped and undoped zinc oxide (ZnO) films on silicon wafers. Various Ar/O₂ gas ratios by volume and sputtering powers were selected for each deposition process. The results demonstrate that the enhanced ZnO films are obtained via Li doping. The average deposition rate for doped ZnO films is twice more than that of the undoped films. Both atomic force microscopy and scanning electron microscopy studies indicate that Li doping significantly contributes to the higher degree of crystallinity of wurtzite–ZnO. X-ray diffraction analysis demonstrates that Li doping promotes the (002) preferential orientation in Li-doped ZnO films. However, an increase in the ZnO lattice constant, broadening of the (002) peak and a decrease in the peak integral area are observed in some Li-doped samples, especially as the form of Li₂O. This implies that doping with Li expands the crystal structure and thus induces the additional strain in the crystal lattice. The oriented-growth Li-doped ZnO will make significant applications in future surface acoustic wave devices.     

Au纳米粒子对ZnO分级结构的气敏特性影响

采用化学浴法制备了花形ZnO纳米棒簇，将平均粒径约40 nm的Au纳米粒子引入ZnO表面得到不同Au修饰量的Au/ZnO复合结构.Uv-vis吸收光谱表明，在Au和ZnO之间存在着作用力使Au的吸收光谱产生红移，这种作用力的存在使复合结构的气敏性能得到了较显著的改善.当Au修饰的质量分数为6%时，复合材料的气敏性能最高，对丙酮气体的灵敏度较纯ZnO提高了约17倍.     

Research progress in ZnO single-crystal: growth,scientific understanding,and device applications

Zinc oxide, a wide band-gap semiconductor, has shown extensive potential applications in high-efficiency semiconductor photoelectronic devices, semiconductor photocatalysis, and diluted magnetic semiconductors. Due to the undisputed lattice integrity, ZnO single crystals are essential for the fabrication of high-quality ZnO-based photoelectronic devices, and also believed to be ideal research subjects for understanding the underlying mechanisms of semiconductor photocatalysis and diluted magnetic semiconductors. This review, which is organized in two main parts, introduces the recent progress in growth, basic characterization, and device development of ZnO single crystals, and some related works in our group. The first part begins from the growth of ZnO single crystal, and summarizes the fundamental and applied investigations based on ZnO single crystals. These works are composed of the fabrication of homoepitaxial ZnO-based photoelectronic devices, the research on the photocatalysis mechanism, and dilute magnetic mechanism. The second part describes the fabrication of highly thermostable n-type ZnO with high mobility and high electron concentration through intentional doping. More importantly, in this part, a conceptual approach for fabricating highly thermostable p-type ZnO materials with high mobility through an integrated three-step treatment is proposed on the basis of the preliminary research.     

Al_2O_3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及掺铝ZnO纳米粉体.利用X射线粉末衍射仪、透射电镜对材料的结构进行了表征.结果表明制备的ZnO及掺铝ZnO纳米材料均属于六方晶系,纤锌矿结构.用纯ZnO和掺铝ZnO做成气敏元件,研究了不同掺杂量对材料的气敏性能的影响.结果表明,铝掺杂均使ZnO对体积分数30×10-6的Cl2的灵敏度有很大的提高,当铝含量为Al2O3/ZnO=0.5%(mol)时,对30×10-6Cl2的灵敏度最高可达800左右.并讨论了纳米氧化物的气敏机理.     

基于ZnO缓冲层的有机太阳能电池数值分析

氧化锌(ZnO)材料具有良好导电性、光透性和稳定性,在光电器件中具有重要用途.利用AMPS-1D探究ZnO作为缓冲层对有机太阳能电池性能的影响.研究发现:添加ZnO缓冲层的有机太阳能电池开路电压、光电转化效率等性能有显著的提高; 电子-空穴产生率和空穴电流密度随着ZnO薄膜厚度增加而减小,而电荷态密度和电子电流密度随着ZnO薄膜厚度增加而增大.     

Excellent ethanol sensor based on multiwalled carbon nanotube-doped ZnO

Multiwalled carbon nanotubes(MWNTs)were synthesized through CVD method,and the gas sensitive materials MWNTs/ZnO were obtained by mixing MWNTs and ZnO.The gas sensing properties of the as-prepared materials were investigated.The results show that the gas sensing properties of ZnO sensor are significantly improved by doping MWNTs.The sensitivity,response time and recovery time to 50 ppm ethanol at 260°C are 46,4 and 20 s,respectively.We also examined the selectivity of 0.1 wt%MWNTs-doped ZnO sensors to different gases.The results show that the sensor possesses an excellent selectivity to ethanol.