多孔硅光致发光研究的最新进展

目前关于多孔硅(PS)的光致发光研究已成为材料科学中的一个新的热点。本文介绍了PS的光致发光机理与特性研究的一些最新进展。     

多孔硅室温光致发光研究

采用电化学和化学溶蚀法在体单晶硅上制备了高孔度多孔硅;室温下测量了蓝光激发的光致可见光谱,发现样品在大气环境中保存时光致发光谱随时间有显著“蓝移”,并渐趋稳定,谱峰位置“蓝移”约40nm;文中给出了发光膜的平面透射电镜形貌和电子衍射照片。“蓝移”和电镜照片的结果能用量子尺寸效应说明。文中还给出了喇曼谱仪上测得的光致发光谱和多孔硅的喇曼位移峰。     

多孔硅光致发光温度特性分析

剖析了多孔硅光致发光与温度有关的实验现象，提出了一个既通过局域在量子线上激子态复合同时又通过一热释过程后经表面态复合的并在不同温度范围起作用的综合发光机理，定性地解释了多孔硅发光的温度特性及其它实验结果。     

多孔硅的氢化、氧化与光致发光

对于刚阳极氧化完的，阳极氧化后紧接着在Ｈ２Ｏ２中光照处理的及长期存放（１０个月）的三种多孔硅样品进行了持续激光照射，不断监视它们的光致发光（ＰＬ）与富利埃变换红外（ＦＴＩＲ）吸收光谱，并在最后对它们作了Ｘ射线光电子能谱（ＸＰＳ）测量，以确定它们所含氧化硅的情况．得出如下几条结论：（１）氢对多孔硅表面的钝化是不稳定的．（２）Ｓｉ—Ｈ键不是发光所必须的．（３）氧对多孔硅表面的钝化是稳定的，纳米硅周围氧化层的存在及其特性对于稳定的多孔硅可见光发射是至关重要的．对激光照射下多孔硅发光的退化提出了新的解释．     

钝化多孔硅的光致发光

选用含有胺基的正丁胺(CH3CH2CH2CH2-NH2)作碳源,采用射频辉光放电法制备碳膜对多孔硅进行碳膜钝化,其光致发光谱和存放实验表明:正丁胺对多孔硅进行钝化是一种十分有效的多孔硅后处理途径.研究了钝化多孔硅的光致发光谱随钝化温度和钝化时间的变化关系,其结果显示:通过调节钝化条件可实现钝化多孔硅最大的发光效率和所需要的发光颜色.     

钝化多孔硅的光致发光

选用含有胺基的正丁胺 (CH3CH2 CH2 CH2 - NH2 )作碳源 ,采用射频辉光放电法制备碳膜对多孔硅进行碳膜钝化 ,其光致发光谱和存放实验表明 :正丁胺对多孔硅进行钝化是一种十分有效的多孔硅后处理途径 .研究了钝化多孔硅的光致发光谱随钝化温度和钝化时间的变化关系 ,其结果显示 :通过调节钝化条件可实现钝化多孔硅最大的发光效率和所需要的发光颜色     

NH3／H2O2溶液腐蚀下多孔硅光致荧光

用光致荧光谱、傅里叶变换红外光谱（ＦＴＩＲ）和扫描电子显微镜（ＳＥＭ）对用阳极氧化法制成的多孔硅层在１％ＮＨ３／Ｈ２Ｏ２溶液中的腐蚀现象进行了研究。红外分析表明，Ｓｉ－Ｏ键和Ｈ－Ｏ键的强度随ＮＨ３／Ｈ２Ｏ２溶液的腐蚀时间的增加而增加，Ｓｉ－Ｈ键强主匠随腐蚀时间增加而减少。光致荧光谱的峰值在腐蚀开始时先下降后上升，半高宽变窄，谱峰的以边明显蓝移。分析研究表明，１％ＮＨ３／Ｈ２Ｏ２溶液对多孔硅层有腐蚀     

国外硅单晶质量研究进展

文章收集了１９８６年以来半导体物理国际会议表的有关硅单晶质量的研究报告和成果。全文区分五大部分。最后一部分介绍了常用和最新发展的测试方法。     

多孔硅的制备和发光特性

本文叙述了多孔硅的制备、多孔形态层的形成机理,以及多孔硅的光致发光现象和理论解释,并且讨论了目前存在的一些问题。     

Photoluminescence enhancement of porous silicon prepared with ammonium sulfide pre-treated silicon

As-grown porous silicon prepared with ammonium sulfide pre-treated silicon show stable photoluminescence characteristics due to high Si–N/PS interface quality and less damage PS with Si–N passivation. After aging in air for 6 months, it shows much stronger photoluminescence intensity and stable wavelength due to higher Si–ON/PS interface quality and less damage of PS with Si–O–N passivation from the oxidation of Si–N.     

Investigation of polarization anisotropy in individual porous silicon nanoparticles

Polarization anisotropy is investigated in single porous silicon nanoparticles containing multiple chromophores. Two forms of nanoparticle samples are studied; low current density (LCD) and high current density (HCD). Photoluminescence measurements reveal that LCD samples exhibit red-shifted spectra and HCD particles display a blue-shifted spectrum. We utilize single molecule spectroscopy to detect the polarization effects of spatially isolated individual nanoparticles, and show that LCD nanoparticles demonstrate strong polarization anisotropy, whereas a dynamic polarization response is collected from HCD nanoparticles.     

雪崩探测器用硅材料中微缺陷的初步探讨

综述了国内外同行对硅材料中微缺陷的有关研究，叙述了微缺陷（下称ＭＤ）对硅雪崩光电探测器（Ｓｉ－ＡＰＤ）性能的影响和消除措施，介绍了目前已有的检测方法，最后进行了讨论。     

GaN growth on porous silicon by MOVPE

GaN films have been grown at 1050 °C on porous silicon (PS) substrates by metalorganic vapour phase epitaxy. The annealing phase of PS has been studied in temperature range from 300 to 1000 °C during 10 min under a mixture of ammonia (NH₃) and hydrogen (H₂). The PS samples were characterized after annealing by scanning electronic microscope (SEM). We observed that the annealing under the GaN growth conditions does not affect the porous structure.For the growth of the active GaN layer we used a thin AlN layer in order to improve wetting between GaN and PS/Si substrate. The growth of AlN and GaN films was controlled by laser-reflectometry. We estimated the porosity of PS samples from the evolution of the reflectivity signal during the AlN growth. The crystalline quality and surface morphology of GaN films were determined by X-ray diffraction and SEM, respectively. Preferential growth of hexagonal GaN with (0002) direction is observed and is clearly improved when the thickness of AlN layer increases. Epitaxial GaN layers were characterized by photoluminescence.     

多孔硅吸收光谱和反射光谱

测定了多孔硅的吸收光谱和反射光谱，结果发现其吸收边对应于可见光区域。同单昌硅要比，其吸收边发生了蓝移，并且吸收强烈。由多孔硅反射谱曲一，利用Ｋ－Ｋ关系对其光学常数进行了简单的计算和分析。     

Complexing of nitrogen with carbon and oxygen in silicon: Photoluminescence studies

We study interactions of nitrogen with carbon and oxygen in crystalline silicon by photoluminescence spectroscopy. Such processes manifest themselves in five photoluminescence lines in the spectral region around 1.6 μm emerging after nitrogen and carbon implantations and furnace annealing with 550° C optimum temperature. Nitrogen and carbon isotope shifts of the lines confirm the incorporation of these atomic species in the optical defects. Nitrogen-oxygen interactions are demonstrated by differences in the lines’ appearance between oxygen-lean float-zone and oxygen-rich pulled silicon starting materials. The data suggests similar basic nitrogen-carbon units in all five defects.