正轴6H-SiC 衬底上3C-SiC薄膜的低压化学气相沉积生长

活性的O-和OH-被认为在苯酚形成过程中起了重要作用．通过低压化学气相沉积，在正轴6H-SiC(0001)衬底上沉积了3C-SiC薄膜，X射线衍射表明薄膜结晶质量良好．研究了生长参数对生长速率的影响，发现硅烷及其分解产物的输运是薄膜生长的限定因素．用原子力显微镜观察薄膜的表面形貌．这些结果表明薄膜的生长符合S-K方式．     

氧化锌薄膜光电功能材料研究的关键问题

氧化锌薄膜光电功能材料是近年来新发展起来的研究课题,由于它在短波长光电信息功能材料方面具有潜在的应用前景而备受关注.为了开发ZnO结型光电器件,目前首先需要解决高质量ZnO单晶薄膜的外延及p型掺杂等关键问题.综合国内外的研究结果,结合我们的工作,叙述了利用多晶格匹配原理通过过渡层在Si衬底上异质外延高质量ZnO薄膜,介绍了用SiC作过渡层生长ZnO薄膜的有关问题.对ZnO的p型掺杂,分析了制备p型ZnO的困难和利用Ⅲ-Ⅴ族共掺杂方法生长p型ZnO的作用和优点.     

Effect of Annealing Temperature on Structural and Optical Properties of N-Doped ZnO Films

Nitrogen-doped ZnO （ZnO：N） films are prepared by thermal oxidation of sputtered Zn3N2 layers on A1203 substrates. The correlation between the structural and optical properties of ZnO：N films and annealing temperatures is investigated. X-ray diffraction result demonstrates that the as-sputtered Zn3N2 films are transformed into ZnO：N films after annealing above 600℃. X-ray photoelectron spectroscopy reveals that nitrogen has two chemical states in the ZnO：N films： the No acceptor and the double donor （N2）o. Due to the No acceptor, the hole concentration in the film annealed at 700℃ is predicted to be highest, which is also confirmed by Hall effect measurement. In addition, the temperature dependent photoluminescence spectra allow to calculate the nitrogen acceptor binding energy.     

Effect of High Temperature Annealing on Conduction-Type ZnO Films Prepared by Direct-Current Magnetron Sputtering

We experimentally find that the ZnO thin films deposited by dc-magnetron sputtering have different conduction types after annealing at high temperature in different ambient. Hall measurements show that ZnO films annealed at 1100℃ in N2 and in 02 ambient become n-type and p-type, respectiveIy. This is due to the generation of different intrinsic defects by annealing in different ambient. X-ray photoelectron spectroscopy and photolumineseence measurements indicate that zinc interstitial becomes a main defects after annealing at 1100℃ in N2 ambient, and these defects play an important role for n-type conductivity of ZnO. While the ZnO films annealed at 1100℃ in O2 ambient, the oxygen antisite contributes ZnO films to p-type.     

Luminescence with Local Distribution and Its Possible Mechanism in Zinc Oxide Micro-Crystallites

The spatial luminescence distribution hi the ZnO micro-crystallite fihns deposited on silicon substrates by CVD at room tempezature is investigated by the cathedolumineseence （CL） image. It has been observed that the CL image of the samples constitutes a certain pattern. The UV emission pattern projective to the （0001） face of ZnO grains consists of a series of lines nearby the grain boundaries . The included angles between any two adjacent lines are almost 120°. What is more, some luminescent lines form a close hexagon similar to ZnO crystalline structure. Such a local distribution propety shows that the UV emission on as-grown ZnO crystallite should be due to some local defects congregated to {1010} facets of ZnO grain rather than free exciton recombination.     

丝光沸石的高温相变

本文从吸水性能、X射线粉晶衍射、差热分析三方面研究了丝光沸石在高温下的相变特点,发现800℃以上丝光沸石转变为非晶固态的相变过程不同于熔体冷凝,气体冷凝形成非晶的过程,有其独特的成因和特点。 关键词：     

非掺杂ZnO薄膜中紫外与绿色发光中心

用直流反应溅射方法在硅衬底上淀积了ZnO薄膜,测量它们的光致发光(PL)光谱,观察到两个发光峰,峰值能量分别为3.18(紫外峰,UV)和2.38eV(绿峰).样品用不同温度分别在氧气、氮气和空气中热处理后,测量了PL光谱中绿峰和紫外峰强度随热处理温度和气氛的变化,同时比较了用FP-LMT方法计算的ZnO中几种本征缺陷的能级位置.根据实验和能级计算的结果,推测出ZnO薄膜中的紫外峰与ZnO带边激子跃迁有关,而绿色发光主要来源于导带底到氧错位缺陷(O_Zn)能级的跃迁,而不是通常认为的氧空 关键词： ZnO薄膜 热处理 光致发光光谱 缺陷能级     

Si基沉积ZnO薄膜的光谱特性

利用同步辐射真空紫外光研究了Si基沉积ZnO薄膜的发射光谱、激发光谱及其湿度依赖。首次观测到高于ZnO禁带宽度的发射带（290nm)，并初步指定其来源。     

热退火对ZnO薄膜表面形貌与椭偏特性的影响

利用原子力显微镜(AFM)和椭偏仪对溅射制备的硅基ZnO薄膜的热退火表面形貌与椭偏特性进行了研究。结果发现：未退火或低温退火(≤850℃)薄膜的形貌呈现较弱的各向异性,晶粒尺寸大小较为均匀,尺寸约为50nm。当经高温退火后,ZnO薄膜的晶粒尺寸明显增大,同时伴随晶粒尺寸分布非均匀化,较大的尺寸可达400nm,而较小的尺寸仅为50nm。此外,椭偏测量表明：椭偏参数在不同的退火温区的变化呈现明显差别;当退火温度高于850℃时,薄膜的结构有明显的变化。     

ZnO:Al薄膜中本征缺陷对光电效应的影响

在直流溅射法制备ZnO薄膜的过程中,通过合适选取溅射时氧氩的压力比,可以显著提高所得n-ZnO／p-Si异质结的光生短路电流,并且对该异质结的光生开路电压没有明显影响,从而可以用这种方法明显提高其光电转化能力。即使是在已经进行了n型掺杂的ZnO薄膜(这里为ZnO：Al)中,改变溅射时氧氩比对光电效应的影响也很明显。通过实验,已经证实了产生这种现象的原因是溅射时氧氩比的改变导致了ZnO薄膜内部的本征缺陷浓度的改变,使得载流子浓度变化而导致的结果。在氧氩压力比约为1：3时,光电转化效率最高。