【作者】 李立珺；

【导师】 郁可；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2010， 博士

【摘要】 低维纳米材料具有与体材料明显不同的物理、化学、生物特性,日益成为当今纳米科技领域的研究热点。氧化物半导体纳米材料具有制备工艺简单、成本低廉、稳定性好等优点,在锂电池、太阳能电池、光降解、光催化、传感器、场发射器件等各领域有广泛的应用前景,因此研究氧化物半导体纳米材料具有重要意义。在本文中,我们对ZnO、Sn02纳米结构的制备、磁性能、发光、传感及场发射等性能进行了系统研究,主要的研究内容和创新点如下：1.Cu掺杂氧化锡纳米线的制备及性能研究。用热蒸发沉积法制备出了Cu掺杂Sn02纳米线结构。所制样品通过XRD,SEM,HRTEM,EDS以及PL等手段进行了表征,研究了Cu催化剂对Sn02纳米结构的发光、场发射及磁性的影响作用。Cu掺杂Sn02纳米线的变温光致发光谱显示,发光中心在590nm,630nm和677nm处。该样品具有良好的场发射性能,开启电场为2.9 V/μm,闽值电场为4.8 V/μm,是一种很有潜力的场发射阴极材料。我们在Cu掺杂Sn02纳米线中观察到了室温铁磁性,而所制样品中并不存在磁性元素,我们初步研究了其磁性起源,并基于第一性原理计算方法研究了Cu离子对磁性的作用。2.Cu掺杂氧化锌纳米片的制备和性能研究。用热蒸发沉积法制备出了Cu掺杂的三角状ZnO纳米片。所制样品通过XRD,SEM,HRTEM,EDS以及PL等手段进行了表征,研究了Cu催化剂对ZnO纳米结构明显的影响作用,ZnO纳米片具有良好的场发射性能,开启电场为3.1 V/μm,场增强因子约为3250,是一种很有潜力的场发射阴极材料。我们在Cu掺杂ZnO纳米片中观察到了室温铁磁性,而所制样品中并不存在磁性元素,我们对该磁性起源进行了初步研究。3.CuO在宏观氧化物纳米材料制备中的催化作用研究。在其他工艺参数不变的条件下,在源材料中加入适量的CuO,可对制备ZnO、Sn02、In2O3等纳米材料起到重要的催化作用。我们用此法成功的制备出了宏观的梳状、带状及树枝状ZnO、Z字形及带状Sn02、宏观In2O3等结构,长度可达1.5cm,重复性良好,容易从中分离出单晶结构单元,为科学研究提供重要的物理平台。我们分析了氧化铜在纳米材料制备中的催化作用,提出了相应的生长机制,并选用单根Z字形Sn02带,研究了其湿度传感性能。4.氧化物纳米材料的制备及场发射性能研究。场发射性能取决于场发射阴极材料的功函数和场增强因子,ZnO、Sn02都是良好的候选阴极材料,该类材料的纳米结构具有丰富的表面形态,有较大的场增强因子,我们通过结构简单、成本低廉的热蒸发法制备出了多种形貌的Sn02、ZnO及Sn掺杂ZnO纳米结构,并分别对其晶体结构,形貌,光致发光等性能进行了表征,研究了源材料配比、温度、气流量、衬底等工艺条件对表面形貌的影响,系统研究了各种纳米结构的场致电子发射性能,结果表明,这些纳米结构具有低的开启电场和阈值电场,高电流发射密度,是良好的场发射阴极材料。更多还原

【Abstract】 Low-dimensional nanomaterials possess significantly different physical, chemical,biological properties with bulk materials, is increasingly becoming a hot area of nanotechnology research.Oxide semiconductor nano-materials have been intensively investigated due to anticipated applications in many areas such as lithium ion electrode materials, solar cells, light degradation, photo catalysis, chemical sensors, cathode emitters of the field emission device and so forth. In this paper, the preparation, magnetism, luminescence, sensor, field emission and other properties of ZnO and SnO2 nano-structures has been systematic studied. The main research content and innovation points are as follows:1.Synthesis and physical properties research of Cu-doped SnO2 nanowires.The Cu-doped SnO2 nanowires were synthesized by thermal chemical vapor transport method. The obtained samples were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectra. The temperature dependence photoluminescence characteristics of the Cu-doped SnO2 nanowires show that two luminescence bands centered at 590 nm and 630 nm, and a right shoulder at 677nm. Field emission measurements demonstrated that the Cu-doped nanobelts possessed good performance with a turn-on field of～2.9 V/μm and a threshold field of～4.8 V/μm. Although the NWs consist of only nonmagnetic elements, room-temperature ferromagnetism is observed and its origin is attributed to both the structure defects and strong p-d ferromagnetic coupling between the local magnetic moment of Cu2+ and the polarized valence electrons of the surrounding oxygen based on first-principles calculations.2.Synthesis and physical properties research of Cu-doped ZnO nanosheets.Triangle-like ZnO nanosheets have been synthesized via conventional thermal evaporation method using CuO as catalyst. The obtained samples were investigated by XRD,SEM, HRTEM, EDS and PL etc.The great influences of Cu catalyst on the morphology of the obtained ZnO nanostructures were investigated. The field emission measurements confirmed that the ZnO nanosheets possessed good performance with a turn-on field of 3.1 Vμm-1 and a field enhancement factor of 3250,which have promising application as a competitive cathode material in FE microelectronic devices.Room temperatures ferromagnetism has been observed in the triangle-like ZnO nanosheets, although the products consist of only nonmagnetic elements.The magnetism origin has been studied.3.Catalysis research of CuO in the preparation of oxide nanomaterials.Other growth conditions are consistent, except that adding CuO powder into the reactant mixture powder, which is supposed to play a critical role in the formation of ZnO,SnO2, In2O3 nanomaterials.We have successfully synthesized ultralong comb, belt and branch-like ZnO, Zigzag and belt like SnO2,and In2O3 structure, reach to about 1.5cm in length.The growth mechanism of the ultralong structures and the catalytic behavior of the copper have been discussed.The humidity sensor based on a single SnO2 zigzag belts has been researched.4.Synthesis and field emission properties of oxide nanomaterials.Field emission properties depend on the work function of the material and the field enhancement factor. Both ZnO and SnO2 are good field emission cathode materials, their nanostructures with abundant surface morphological and large field enhancement factor. We have successfully synthesized various ZnO,SnO2 and Sn-doped ZnO nanostructures.Obtained samples were investigated by XRD,SEM, HRTEM,and PL etc.The field emission measurements confirm that these structures possessed good performance with lower turn-on field and threshold field,higher field emission current density, which have promising application as a competitive cathode material in FE microelectronic devices.更多还原