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.     

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，１×１０（１２）～１×１０（１５）／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Ｅｒ（３＋）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Ｅｒ（３＋）发光增强的原因．     

掺铒硅基材料发光的新途径

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氮团簇离子注入单晶硅的光致发光谱研究

氮团簇离子N⁺₁₀注入单晶硅直接诱发其表层转化为纳米晶结构, 导致光学性质发生显著变化. 在250—320nm波段的紫外光激励下,在330—500nm光区出现明显的光发射带,并在360nm附近产生强度极高、单色性良好的发射峰,其强度达到N⁺注入试样或基底的5倍,是N⁺₂注入试样的1.5倍. 在可见光区的730nm附近和近红外区的830nm附近也出现发光带. 所有上述发光都非常稳定,可长时间保持其发 关键词： 光致发光 团簇离子注入 硅单晶 纳米晶结构     

氧和铒共注入硅的卢瑟福背散射和发光研究

将铒和氧共注人硅中,卢瑟福背散射分析表明,退火后铒的分布剖面因共注入氧的剂量而异。在高氧剂量下,退火后铒保持退火前的剖面不变,样品再结晶良好。在中等氧剂量下,退火后铒的分布剖面出现双峰。认为退火过程中形成了铒—氧复合物。复合物的形成减缓了铒的偏析和扩散,影响了铒的削面再分布。铒和氧离子注入剂量的系列实验证实了氧在Er3+发光中有重要作用。     

Ce3+注入对不同尺寸的nc-Si/SiO2 超晶格发光特性的影响

通过电子束蒸发方法以及高温退火处理,得到nc-Si/SiO₂超晶格。将样品分别注入剂量为2.0×10¹⁴ cm^-2和2.0×10¹⁵ cm^-2的Ce³⁺,再对其进行二次退火处理,获得多组样品。通过对样品光致发光光谱的分析发现,样品发光强度的变化不仅受到Ce³⁺注入剂量的影响,而且也受到nc-Si颗粒大小的影响。在相同注入计量和相同的二次退火处理温度下,nc-Si颗粒较大的样品经Ce³⁺注入后其发光强度增强较为明显。     

多孔硅中的1.54μm光发射

本文报道了利用离子注入技术制备多孔硅中Er³⁺的1.54μm光发射发光材料的实验,并对样品的低温光致发光特性进行了实验研究。实验表明多孔硅中的Er³⁺发光与单晶硅中的Er³⁺发光(同样注入条件,退火工艺制备)相比,发光强度有成数量级的提高,同时发光峰更宽,伴线更丰富。     

用MEVVA低能离子注入制备表层SiC/Si异质结构及其室温的光致发光特性

利用金属蒸汽真空弧离子源（MEVVA）进行离子束合成,制备了过剂量C^＋离子注入到单晶硅衬底的样品。然后利用热退火,在表层制备了连续8-SiC层,形成表层SiC／Si的异质结构。利用傅里叶变换红外光谱（FTIR）对其成键特征和微结构进行了分析,通过光电子能谱分析（XPS）和原子力显微镜（AFM）分析了样品的成分分布及其表面形貌。最后对其室温下的光致发光特性随热退火的时间和温度的变化进行了研究。结果表明：光致发光谱（PL）表现出430,560nm两个发光峰,分别对应于纳米碳化硅和块状立方碳化硅发光的特征峰。我们认为小颗粒的晶化碳化硅的尺寸及其相对比例对PL发光峰位和强度有较大的影响,用纳米晶粒量子效应（NSUQC）理论和表面态理论对发光现象及其变化规律进行了初步的解释。     

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。     

Enhanced Photoluminescence Intensity of Silicon–Germanium Nanoparticles: Silica Thin Films by Annealing in Forming Gas

Silicon–germanium nanoparticles are prepared by ion implantation and annealing method. Further annealing treatment is carried out in forming gas to passivate nonradiative defects around nanoparticles. Time-resolved photoluminescence measurements were examined to reveal the local environment surrounding the nanoparticles. With the increase in oxygen gas content, photoluminescence intensity from specimen is enhanced by ～5 times and its decay time τ decreases from 23.2 to 1.6 µs. Oxygen gas is considered to be an effective passivating gas for this kind of specimen.     

POSITRON ANNIHILATION STUDY ON SURFACE STRUCTURE OF BIOLOGICAL SAMPLES IMPLANTED BY IONS WITH LOW ENERGY

The organic materials of biological samples, such as lima bean and peanut, were implanted respectively by nitrogen ions with an energy of 100 keV and vanadium ions with an energy of 200 keV. The positron annihilation lifetime spectra of implanted and non-implanted samples were compared with each other especially in τ₃ and I₃. The experimental results showed that before implantation there were many small holes with diameters of 0.48 and 0.7 nm respectively in lima bean and peanut. After ion implantation, the size of holes would be changed because of organism cross linking and scission. The effective penetration range of implantation of ions with low energy into biological samples is about 200μm.     

Investigation of the lateral spread of erbium ions implanted in silicon crystal

The erbium ions at energy of 400 keV and dose of 5×10 15 ions/cm 2 were implanted into silicon single crystals at room temperature at the angles of 0,45 and 60.The lateral spread of 400 keV erbium ions implanted in silicon sample was measured by the Rutherford backscattering technique.The results show that the measured values were in good agreement with those obtained from the prediction of TRIM’98 (Transport of Ions in Matter) and SRIM2006 (Stopping and Range of Ions in Matter) codes.     

Effect of hydrogen defects on nanocrystallite layers of Si solar cells by hydrogen implantation

The Si solar cells were irradiated with high energy hydrogen ions of 10, 30, 60 and 120?keV at the dose rate of 10¹⁷ H⁺ ions (proton)/cm². The structural, optical and electrical properties of the implanted samples and fabricated cells were studied. The implantation induced defects bringing structural changes before and after annealing was evidenced by the transmission electron microscopy. The Raman spectrum showed a change of crystalline to amorphous state at 480?cm^?1 when the sample was implanted by hydrogen ion of 30?keV energy. Formation of nanocrystallite layers were observed after annealing. The electroluminescence images showed that hydrogen-related defect centers were involved in the emission mechanism. The photoluminescence emission from the implanted cells was attributed to nanocrystallite layers. From current–voltage measurements, the conversion efficiencies of implanted Si solar cells were found lower than the un-implanted reference cell. The ion implantation did not passivate the defects rather acted as recombination centers.     

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     

磁控溅射淀积掺Er富Si氧化硅膜中Er~(3 ) 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 1.5 4和 1.38μm两个发光峰 ,其中 1.5 4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 1.5 4μm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 1.5 4μm发光峰强度与 1.38μm发光峰强度相互关联 ,对此进行了讨论     

SiGe/Si量子阱的低温光荧光和电注入发光

使用Si-MBE生长了阶梯形折射率分布SiGe/Si量子阱材料,在低温下观测到无声子参与的光荧光和电注入发光。阶梯形折射率分布SiGe/Si电子阱结构有利于提高发光效率。讨论了这种结构的光学和电学特性。     

Formation of As enriched layer by steam oxidation of As-implanted Si

Segregation of implanted As during steam oxidation of Si wafers is shown to result in a highly enriched, thin layer of As at the interface between the oxide and the underlying Si. Also, the oxidation rate was found to increase by as much as a factor of ∼2 depending on the depth distribution and fluence of the implanted As impurity. The thin As layer collected at the interface can be used in the design of very shallow junctions. This mechanism enables the formation of a narrow, degenerately doped layer of Si, which can be tailored to have a thickness of only few monolayers depending on the fluence of the implantation used.     

Ion implantation into amorphous Si layers to form carrier‐selective contacts for Si solar cells

This paper reports our findings on the boron and phosphorus doping of very thin amorphous silicon layers by low energy ion implantation. These doped layers are implemented into a so‐called tunnel oxide passivated contact structure for Si solar cells. They act as carrier‐selective contacts and, thereby, lead to a significant reduction of the cell's recombination current. In this paper we address the influence of ion energy and ion dose in conjunction with the obligatory high‐temperature anneal needed for the realization of the passivation quality of the carrier‐selective contacts. The good results on the phosphorus‐doped (implied V_oc = 725 mV) and boron‐doped passivated contacts (iV_oc = 694 mV) open a promising route to a simplified interdigitated back contact (IBC) solar cell featuring passivated contacts. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

煤制氢零排放系统

氢能在未来可持续能源系统中,可望成为与电力并重而又互补的主要终端能源。煤制氢具有重要的战略地位。本文构造并分析煤制氢零排放系统。主反应器中部分炭转化为氢的系统冷煤气效率可达９０％,分析揭示了系统中的热集成情况和能量平衡。     

Photoluminescence of focused ion beam implanted Er3+:Y2SiO5 crystals

Erbium‐doped low symmetry Y₂SiO₅ crystals attract a lot of attention in perspective of quantum information applications. However, only doping of the samples during growth is available up to now, which yields a quite homogeneous doping density. In the present work, we deposit Er³⁺‐ions by the focused ion beam technique at yttrium sites with several fluences in one sample. With a photoluminescence study of these locally doped Er³⁺:Y₂SiO₅ crystals, we are able to evaluate the efficiency of the implantation process and develop it for the highest efficiency possible. We observe the dependence of ion activation after the post‐implantation annealing on the fluence value. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)