稀土铒离子注入多孔硅的发光

稀土离子Er注入多孔硅中.在350keV能量,1×1012~1×1015/cm2剂量范围内,注入后的多孔硅仍保持明亮的可见光发射.退火后,在近红外区测到1.54μm附近Er3+的特征发射.其发射强度比硅单晶对照样品明显增强,实验表明这增强作用来源于多孔硅的表面发光层.电化学制备过程中在表面层中带入的O、C、F等多种杂质可能是Er3+发光增强的原因.     

Ce~(3+)注入对超晶格中硅纳米晶光致发光强度的影响

研究了铈离子注入和二次退火等因素对硅纳米晶(nc-Si)发光强度的影响.利用电子柬蒸发以及高温退火得到nc-Si/SiO2超晶格结构.随后将该结构样晶分别注入2.0×1014cm2和2.0×1015cm-2剂量的铈离子(Ce3+),再分别以不同温度对其进行二次退火,获得多种样品.通过对样品光敏发光光谱的分析发现,Ce3+注入后未经过二次退火的样品发光强度急剧下降.二次退火后的样品,随着退火温度的升高,样品的光致发光灶度逐渐增强,但当温度超过600℃时,发光强度反而下降,600℃为二次退火的最佳退火温度.注入适当剂量的Ce3+,其发光强度可以超过未注入时的发光强度,Ce3+的注入存在饱和剂量.研究表明,样品发光强度的变化受到铈离子注入剂量和注入后二次退火温度等因素的影响,并且存在着Ce3+到nc-Si的能量传递.     

氢钝化对硅纳米晶发光强度的影响

通过热蒸发方法在单晶硅衬底上沉积了SiO/SiO₂超晶格样品,在氮气保护下对样品进行高温退火,得到硅纳米晶/SiO₂超晶格结构。随后将该结构样品分别注入3.0×1014和3.0×1015 cm-2两种剂量的H+。通过对样品的光致发光光谱的分析发现,H+注入后未经过二次退火的样品发光强度急剧下降;二次退火后的样品,随着退火温度的升高,发光强度逐渐增强;注入足够剂量的H+,其发光强度可以远远超过未注入时的发光强度。研究表明,样品发光强度的变化取决于样品内部缺陷面密度的改变,而缺陷面密度是由氢离子的注入剂量和注入后再退火的温度等因素决定的。     

磷离子注入速率对4H-SiC(0001)晶格恢复与电阻率降低的影响

高剂量的磷离子注入4H-SiC(0001)晶面，注入速率从1.0×1012到4.0×1012 P+ cm-2s-1变化，而注入剂量固定为2.0×1015 P+ cm-2。室温注入，1500oC的高温下退火。利用光荧光和拉曼谱分析注入产生的晶格损伤以及退火后的残余缺陷。通过霍耳测试来分析注入层的电学性质。基于上述测试结果，发现通过减小磷离子的注入速率，极大地减少了注入层的损伤及缺陷。考虑到室温注入以及相对较低的退火温度(1500 oC)，在注入速率为1.0×1012 P+ cm-2s-1及施主浓度下为4.4×1019 cm-3的条件下，获得了非常低的方块电阻106 Ω/sq。     

磁控溅射淀积掺Er富Si氧化硅膜中Er3+ 1.54μm光致发光

用磁控溅射淀积不同富Si程度的掺Er富Si氧化硅薄膜.室温下测量其光致发光谱,观察到各谱中都含有1.54和1.38μm两个发光峰,其中1.54和1.38μm的光致发光峰分别来自Er³⁺和氧化硅中某种缺陷.系统研究了Er³⁺1.54μm光致发光峰强度对富Si程度及退火温度的依赖关系.还发现1.54μm发光峰强度与1.38μm发光峰强度相互关联,对此进行了讨论 关键词： Er 富Si氧化硅 光致发光 纳米硅     

离子注入及后退火方法制备SiO2基质中镶嵌ZnO纳米粒子的结构和光学性质

利用离子注入及后退火方法在光学纯的石英基片中注入3×1017cm-2剂量的Zn离子,然后在不同的退火条件下制备了高质量的镶嵌在SiO2基质中的ZnO纳米粒子.X射线衍射光谱的实验结果表明在氧气气氛、700℃退火温度和2小时退火时间条件下,得到了(002)择优取向镶嵌在SiO2基质中的ZnO纳米粒子;而在700℃退火温度、N2和O2气氛下顺次退火1小时,得到了比上述条件(002)择优取向更好的ZnO纳米粒子.室温下对用上述两种条件制备的镶嵌在SiO2基质中的ZnO纳米粒子观察到了自由激子吸收峰.室温光致发光谱中观察到了ZnO纳米粒子位于3.29eV处的强紫外发射,紫外发射强度与深能级发光强度之比为40,紫外发射峰的半高宽为96meV,晶体质量类似于分子束外延方法生长的ZnO.在低温(77K)光致发光谱中,较强的自由激子的紫外发光峰仍然存在.     

溶胶-凝胶(sol-gel)法制作掺铒Al2O3薄膜及其光致发光光谱特性测量

介绍一种用溶胶-凝胶方法制作掺铒Al₂O₃薄膜的工艺.实验测量了薄膜样品的光致发光光谱特性.结果表明光致发光光谱的峰值波长为1.536 μm,半值宽度为34 nm;同时测量了光致发光光谱的峰值强度与泵浦功率、掺铒浓度及退火温度之间的关系.     

铒掺杂富硅热氧化SiO2/Si发光薄膜的显微结构

利用金属蒸气真空弧 (MEVVA)离子源将稀土元素Er离子掺杂到富硅热氧化SiO2 /Si薄膜中。卢瑟福背散射 (RBS)和X 射线电子能谱仪 (XPS)分析表明 ,Er浓度可达原子百分数 (x)～ 10 ,即Er的原子体浓度为～ 10 2 1·cm-3 。XPS研究发现 ,随着Si注量增大 ,退火态样品表面硅含量增多 ,热氧化硅含量减少。反射式高能电子衍射 (RHEED)和原子灵敏度因子法 (AFM)研究表明 ,样品表面没有大量Er析出或铒硅化物形成 ,退火后表层中Si外延再生长、有针状微晶硅颗粒形成。在 77K及室温下 ,研究了Er掺杂富硅热氧化SiO2 /Si薄膜的近红外区 1 5 4μm附近光致发光光谱     

室温下掺Er富硅氧化硅和掺Er富硅氮化硅的光致发光及其退火

用磁控溅射淀积掺Er氧化硅、掺Er富硅氧化硅、掺Er氮化硅和掺Er富硅氮化硅薄膜,室温下测量这四种薄膜的光致发光（PL）谱,观察到这四种薄膜都具有1.54μm的峰位,其强度与薄膜的退火温度有关。为了确定1.54μmPL的最佳退火温度,这些薄膜都分别在600,700,800,900,1000,1100℃的温度下同时退火,发现两种富硅薄膜的最佳退火温度是800℃,不富硅的两种薄膜的最佳退火温度是900℃。样品的1.54μmPL最强,且800℃退火的掺Er富硅氧化硅薄膜的1.54μm峰强度是最强的,比不富硅的强了约20倍,还观察到这四种薄膜都具有1.38μm的PL带,且掺Er富硅氧化硅和掺Er富硅氮化硅这两种薄膜的PL在强度上1.38μm峰与1.54μm峰有一定的关系。     

基于离子注入技术的ZnMnO半导体材料的制备及光谱表征

通过离子注入技术制备了ZnMnO半导体材料，研究离子注入剂量与退火对材料光谱性质的影 响.Raman光谱研究发现，575cm^-1处声子模展宽是由高剂量Mn注入引起的缺陷所 致，退火样品528cm^-1振动模来自Mn相关的杂质振动.室温光致发光谱表明，退 火对高剂量注入样品的可见发光带有增强作用. 关键词： ZnMnO 离子注入 Raman光谱 室温光致发光     

非晶碳化硅材料与光学微腔的制备与发光

利用等离子体化学气相沉积技术在100℃的衬底温度下,制备了具有不同组分比的系列非晶碳化硅薄膜。结合傅里叶变换红外光谱与喇曼光谱对所制备的薄膜微结构进行了表征与分析,同时,对具有不同组分比的非晶碳化硅薄膜室温光致发光性质进行了系统的研究。结果表明在Ar⁺离子激光和Xe灯紫外光的激发下,不同组分的样品显示出不同的光致发光特性,并对样品的发光特性与其微结构的联系进行了讨论。在此基础上,用碳化硅薄膜设计和制备了全固体光学微腔,研究了微腔对碳化硅发光行为的调制作用。     

Ti离子注入和退火对ZnS薄膜结构和光学性质的影响

利用真空蒸发法在石英玻璃衬底上制备了ZnS薄膜,将能量80 keV,剂量1×10¹⁷ cm^-2的Ti离子注入到薄膜中,并将注入后的ZnS薄膜进行退火处理,退火温度500—700 ℃.利用X射线衍射（XRD）研究了薄膜结构的变化,利用光致发光（PL）和光吸收研究了薄膜光学性质的变化.XRD结果显示,衍射峰在500 ℃退火1 h后有一定程度的恢复;光吸收结果显示,离子注入后光吸收增强,随着退火温度的上升,光吸收逐渐降低,吸收边随着退火温度的提高发生蓝移;PL显示,薄 关键词： ZnS薄膜 离子注入 X射线衍射 光致发光     

Surface disorder in c-Si induced by swift heavy ions

The disorders induced in crystalline silicon (c-Si) through the process of electronic energy loss in the swift heavy ion irradiation were investigated. A number of silicon <1 0 0> samples were irradiated with 65 MeV oxygen ions at different fluences, 1×10¹³ to 1.5×10¹⁴ ions/cm², and characterized by the Raman spectroscopy, the optical reflectivity, the X-ray reflectivity, the atomic force microscopy (AFM) and the X-ray diffraction (XRD) techniques. The intensity, redshift, phonon coherence length and asymmetric broadening associated with the Raman peaks reveal that stressed and disordered lattice zones are produced in the surface region of the irradiated silicon. The average crystallite size, obtained by analyzing Raman spectrum with the phonon confinement model, was very large in the virgin silicon but decreased to<100 nm dimension in the ion irradiated silicon. The results of the X-ray reflectivity, AFM and optical reflectivity of 200–700 nm radiation indicate that the roughness of the silicon surface has enhanced substantially after ion irradiation. The diffusion of oxygen in silicon surface during ion irradiation is evident from the oscillation in the X-ray reflectivity spectrum and the sharp decrease in the reflectivity of 200–400 nm radiation. The rise in temperature, estimated from the heat spike model, was high enough to melt the local silicon surface. The results of XRD indicate that lattice defects have been induced and a new plane <2 1 1> has been formed in the silicon <1 0 0>after ion irradiation. The results of the present study show that the energy deposited in crystalline silicon through the process of electronic energy loss ～0.944 keV/nm per ion is sufficient to induce disorders of appreciable magnitude in the silicon surface even at a fluence of ～10¹³ ions/cm².     

离子注入Si损伤分布的光谱法多层分析

应用多层模型和最优化方法,由实验测得的离子注入Si的椭偏光谱以及单晶Si和离子注入非晶Si的光学常数,能分析离子注入Si的损伤分布。我们测量了2.1—4.6eV能量范围的椭偏光谱和光学常数,建立了多层计算模型和最优化方法。在模拟分析的基础上,计算了能量为40keV,剂量分别为4×10¹³和1.4×10¹⁴cm^-2的As⁺注入Si的损伤分布,并与背散射测量的结果比较。用多层模型和最优化方法也能从光谱分析其它物理量的分布,只要这些物理量对光学性质有显著的影响,并且在测量过程中不随光子能量而改变。 关键词：     

Si(113)表面原子结构的低能电子衍射研究

利用低能电子衍射(LEED)研究了离子轰击加退火处理的和淀积外延的两种Si(113)表面的原子结构。发现对于经750—800℃退火后的两种Si(113)表面,当其温度高于600℃时存在1×1非再构表面相。随着样品温度缓慢地冷却至室温,Si(113)-1×1表面经过3×1(约600—400℃)最后转变为3×2再构。当退火温度为600℃时,则只出现3×1再构,室温下的3×2和3×1表面都是很稳定的。讨论了表面杂质对Si(113)表面原子结构的影响。在衬底温度为580℃的Si(113)表面上进行淀积生长,当外延 关键词：     

Effect of bombardment with iron ions on the evolution of helium,hydrogen, and deuterium blisters in silicon

The effect of bombardment with iron ions on the evolution of gas porosity in silicon single crystals has been studied. Gas porosity has been produced by implantation hydrogen, deuterium, and helium ions with energies of 17, 12.5, and 20 keV, respectively, in identical doses of 1 × 10¹⁷ cm^–2 at room temperature. For such energy of bombarding ions, the ion doping profiles have been formed at the same distance from the irradiated surface of the sample. Then, the samples have been bombarded with iron Fe¹⁰⁺ ions with energy of 150 keV in a dose of 5.9 × 10¹⁴ cm^–2. Then 30-min isochoric annealing has been carried out with an interval of 50°C in the temperature range of 250–900°C. The samples have been analyzed using optical and electron microscopes. An extremely strong synergetic effect of sequential bombardment of silicon single crystals with gas ions and iron ions at room temperature on the nucleation and growth of gas porosity during postradiation annealing has been observed. For example, it has been shown that the amorphous layer formed in silicon by additional bombardment with iron ions stimulates the evolution of helium blisters, slightly retards the evolution of hydrogen blisters, and completely suppresses the evolution of deuterium blisters. The results of experiments do not provide an adequate explanation of the reason for this difference; additional targeted experiments are required.     

Ti-2Al-2.5Zr合金He离子辐照效应研究

 在Ti-2Al-2.5Zr合金中注入能量为75 keV的He离子，注入剂量分别为5×10¹⁶cm^-2，1×10¹⁷ cm^-2。通过显微硬度测量和剖面电子显微观察，研究了He离子对Ti-2Al-2.5Zr合金力学性能和显微组织的影响。结果表明:样品的显微硬度随He离子注量的增加而升高，在温度为350和550 ℃的Ar气中退火后硬度有所下降。剖面电子显微观察发现有位错环和He气泡生成，退火后He气泡有长大、缺陷有回复的趋势。辐照产生的位错环是辐照后硬度升高的直接原因，其退火发生回复又引起硬度随退火温度的升高而降低。     

Effects of silicon negative ion implantation in semi-insulating gallium arsenide

ABSTRACT

In the present work, effects of silicon negative ion implantation into semi-insulating gallium arsenide (GaAs) samples with fluences varying between 1?×?10¹⁵ and 4?×?10¹⁷?ions?cm^?2 at 100?keV have been described. Atomic force microscopic images obtained from samples implanted with fluence up to 1?×?10¹⁷?ion?cm^?2 showed the formation of GaAs clusters on the surface of the sample. The shape, size and density of these clusters were found to depend on ion fluence. Whereas sample implanted at higher fluence of 4?×?10¹⁷?ions?cm^?2 showed bump of arbitrary shapes due to cumulative effect of multiple silicon ion impact with GaAs on the same place. GXRD study revealed formation of silicon crystallites in the gallium arsenide sample after implantation. The silicon crystallite size estimated from the full width at half maxima of silicon (111) XRD peak using Debye-Scherrer formula was found to vary between 1.72 and 1.87?nm with respect to ion fluence. Hall measurement revealed the formation of n-type layer in gallium arsenide samples. The current–voltage measurement of the sample implanted with different fluences exhibited the diode like behavior.     

Effects of high-dose Ge ion implantation and post-implantation annealing on ZnO thin films

This paper reports that ion implantation to a dose of 1×10¹⁷ ions/cm² was performed on c-axis-orientated ZnO thin films deposited on (0001) sapphire substrates by the sol-gel technique. After ion implantation, the as-implanted ZnO films were annealed in argon ambient at different temperatures from 600-900℃. The effects of ion implantation and post-implantation annealing on the structural and optical properties of the ZnO films were investigated by x-ray diffraction (XRD), photoluminescence (PL). It was found that the intensities of (002) peak and near band edge (NBE) exitonic ultraviolet emission increased with increasing annealing temperature from 600-900℃. The defect related deep level emission (DLE) firstly increased with increasing annealing temperature from 600- 750℃, and then decreased quickly with increasing annealing temperature. The recovery of the intensities of NBE and DLE occurs at \sim 850℃ and \sim 750℃ respectively. The relative PL intensity ratio of NBE to DLE showed that the quality of ZnO films increased continuously with increasing annealing temperature from 600 - 900℃.     

Ellipsometric studies of annealing of SiO2 layers during the formation of light-emitting Si nanocrystals in them

Annealing of SiO₂ layers with excessive Si leading to the formation of silicon nanocrystals capable of fluorescing in the visible region owing to quantum-dimensional limitations is studied by the ellipsometry method. Excessive Si was introduced in SiO₂ layers by ion implantation with an energy of 25 keV and a dose of 5× 10¹⁶ cm^?2. Isochronous (10³ s) annealings were carried out in a temperature interval of 200–1150°C with a step of 100°C. An LÉF-2 ellipsometer with a 70° angle of incidence at a wavelength of 632.8 nm was used for the measurements. Fluorescence excited by a nitrogen laser was monitored concurrently. It is found that variations in optical constants of the layers at each step of annealing over the entire temperature range studied are clearly detected by ellipsometry. Variations in optical parameters of excessive Si are calculated in the Bruggeman approximation. They are found to correspond to individual stages of the formation of nanoprecipitates revealed earlier by other techniques. Nanocrystals proper producing intense visible photoluminescence are formed at annealing temperatures of 1000°C and higher.