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Porous silicon fabricated via Pt-assisted chemical etching of p-type Si (1 0 0) in 1:1:1 EtOH/HF/H2O2 solution possesses a longer durability in air and in aqueous media than anodized one, which is advantageous for biomedical applications. Its surface SiHx (x = 1 and 2) species can react with 10-undecylenic acid completely under microwave irradiation, and subsequent derivatizations of the end carboxylic acid result in affinity capture of proteins. We applied two approaches to produce protein microarrays: photolithography and spotting. The former provides a homogeneous microarray with a very low fluorescence background, while the latter presents an inhomogeneous microarray with a high noise background. 相似文献
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理论上,采用Bruggeman有效介质近似,研究了有机吸附物对多孔硅微腔的折射率及其光致发光谱的影响.实验上,采用计算机控制的电化学腐蚀法制备了多孔硅微腔样品,并利用机械泵油的蒸气分子与该微腔样品进行相互作用.研究发现,多孔硅微腔发射的窄化光致发光谱对泵油蒸气分子的吸附与脱附很敏感,与之伴随的是该窄化光致发光谱发生明显的峰位移动(可达71nm)和强度变化.结合Bruggeman近似和表面态对多孔硅发光的影响,对实验结果进行了定性解释.实验结果与理论模拟结果符合较好.
关键词:
Bruggeman近似
吸附物
多孔硅微腔
光致发光谱 相似文献
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在多孔硅衬底上用射频溅射法沉积了非晶的SiC:Tb薄膜. 对样品在N2中进行了不同温度的退火处理. 用傅里叶红外变换谱分析了样品的结构.用荧光光谱仪测试了样品的光致发光,在紫外、可见光区域观测到了强的发光峰.发现随着衬底加热温度和样品退火温度的变化,发光峰有明显的强度变化和微弱的蓝移现象.分析了产生这种现象的机理,得出了紫外区域的发光峰是由于氧缺乏中心引起的,而可见区的发光是由于Tb离子产生的.
关键词:
碳化硅
光致发光
氧缺乏中心
多孔硅 相似文献
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Yunsen Zhang Donglai Liu Xue Bai Huabing Song Wenyu Li Xiaosong Sun 《Journal of luminescence》2010,130(6):1005-1473
This very paper is focusing on the investigation of porous silicon preparation with n-type silicon wafer by means of electrochemical anodization in the dark and, particularly, on its stable ultraviolet photoluminescence emission. A lateral electrical potential was applied, for this purpose, on silicon wafers, driving the electrons away and letting holes appear on the surface of the silicon wafer to enhance the electrochemical etching process. Characterizations have been made with scanning electronic microscope, fluorescence spectrophotometer and Fourier transform infrared spectroscope. An ultraviolet photoluminescence emission of 370 nm is found in the as-prepared n-type porous silicon, which seems to be well associated with the formation of oxygen-related species (twofold coordinated silicon defect) during the anodic oxidation. The result characterized by photo-bleaching performance indicates that the ultraviolet photoluminescence emission is so stable—only 7% reduction within 3600 s. Meanwhile the morphology of as-prepared n-type porous silicon is investigated. 相似文献
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M. Sendova-Vassileva D. Dimova-Malinovska M. Kamenova A. Kakanakova-Georgieva Ts. Marinova 《Journal of luminescence》1998,80(1-4):179-182
Porous silicon (PS) is studied by stepwise peeling of the surface layer to clarify the non-uniformity in the photoluminescence (PL) and correlate it with the in-depth chemical bonding and structure of the 30 μm thick layer. The PL intensity grows by an order of magnitude after the peeling off of the first 10 μm and decreases five times in the next 5 μm while the peak maximum position shifts from 730 to 800 nm. X-ray photoelectron spectroscopy (XPS) measurements show that Si–Si and Si–O bonds are present both on the surface and below, and the preferential oxidation state of silicon changes from 3+ and 4+ on the surface to 1+ and 2+ below 10 μm. Using Raman spectroscopy silicon nanocrystals are shown to exist. Their mean size can be estimated at about 3 nm. These results show that the strongest PL comes from a region in the PS layer where silicon nanocrystallites are surrounded by oxides with a low level of oxidation and not from the strongly oxidized surface layer. 相似文献
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Rao Huang Li-bo Ma Jian-ping Ye Yong-qian Wang Ze-xian Cao 《Frontiers of Physics in China》2008,3(2):173-180
High-density silicon nanoparticles with well-controlled sizes were grown onto cold substrates in amorphous SiN
x
and SiC matrices by plasma-enhanced chemical vapor deposition. Strong, tunable photoluminescence across the whole visible
light range has been measured at room temperature from such samples without invoking any post-treatment, and the spectral
features can find a qualitative explanation in the framework of quantum confinement effect. Moreover, the decay time was for
the first time brought down to within one nanosecond. These excellent features make the silicon nanostructures discussed here
very promising candidates for light-emitting units in photonic and optoelectronic applications.
相似文献
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分别将特定杂质铜和铝引入多孔硅后,观察到了杂质铜和铝所引起的附加发光带:对于没有掺铜的多孔硅,其光致发光谱只有一个发光带;而掺过铜的多孔硅,其光致发光谱出现两个发光带,其中能量较低的发光带随主发光带而变化。在掺铝多孔硅的光致发光谱中,则出现4个与铝杂质能级有关发光带。我们认为上述与杂质有关的发光带是由截流子在杂质深能级上复合所致。 相似文献
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The nanostructural and photoluminescence (PL) features of nanoporous Si (NPS) were investigated in terms of various process parameters such as current density, etching time and oxidation conditions. The NPS was prepared by electrochemical anodic etching of p-type (0 0 1) Si wafers of 4 Ω cm resistivity in HF solution. The pores are of polygon-type columns with 5, 6 and 7 side walls. The average diameter of the column-shaped pores is critically determined by the current density, while the etching time plays an important role on the pore depth; in particular, when the current densities of 30 and 100 mA/cm2 were applied, the pore diameters were 9 nm and 3.3 μm, respectively. The variation in the PL characteristics of the NPS with oxidation condition and etching current density was measured and then related with their structural changes. The aging and thermal treatments produce oxidation and lattice distortion in the NPS. The degree of deviation from the as-prepared NPS during aging or thermal treatment seems to depend on the nanostructure as well as morphology of the NPS. It is found in this study that etching current density plays an important role on such structural features of the NPS. 相似文献
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This paper describes a new method to create nanoscale SiO2 pits or channels using single-walled carbon nanotubes (SWNTs) in an HF solution at room temperature within a few seconds. Using aligned SWNT arrays, a pattern of nanoscale SiO2 channels can be prepared. The nanoscale SiO2 patterns can also be created on the surface of three-dimensional (3D) SiO2 substrate and even the nanoscale trenches can be constructed with arbitrary shapes. A possible mechanism for this enhanced etching of SiO2 has been qualitatively analysed using defects in SWNTs, combined with H3O+ electric double layers around SWNTs in an HF solution. 相似文献
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The morphology control of aligned silicon nanowires (SiNWs) is highly desirable as SiNWs demonstrated high prospect in a variety of applications. Besides the control over length, shape and distribution of aligned SiNWs, the fine‐tuning of tilting angles thereof also attracted intense interest. Up to now, only several discrete tilting angles have been reported. In this Letter, the ability to fine‐tune the tilting angle of SiNWs is demonstrated and the range that can be achieved is identified. Our technique employs the anisotropic characteristic of the etching process using custom‐produced off‐cut Si wafers of various orientations as substrates. With this technique, a uniquely favoured etching direction can result and the tilting angle can be precisely controlled. Tilted SiNWs with tilting angles from 0° to 50° relative to the wafer normal were obtained. The mechanism of the tilting angle manipulation is also discussed. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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GUO Hengqun 《Chinese Journal of Lasers》1994,3(6):557-563
Photoluminescence quenching of porous silicon by noble metal adsorbates¥GUOHengqun(DepartmentofAppliedPhysics,HuaqiaoUniyersi... 相似文献
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V. V. Filippov V. P. Bondarenko P. P. Pershukevich V. S. Khomenko 《Journal of Applied Spectroscopy》1997,64(4):514-517
We obtained porous silicon films modified at room temperature by an Eu3+-containing polymer complex. The most intense photoluminescence of Eu3+ implanted in the porous silicon was observed at the wavelengths of 611, 618, 691, and 704 nm. In this case, the intensity
of the intrinsic photoluminescence of strongly irradiated specimens of porous silicon decreased, while the intensity of weakly
emitting films multiply increased. An investigation of the photoexcitation spectra made it possible to establish the effect
of Eu3+-containing complexes on the mechanism underlying the excitation of photoluminescence of porous silicon.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 499–501, July–August, 1997. 相似文献
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In this paper, we present a study on the porous silicon surface with the aim of filling porous silicon layers with organics. We discuss on two processes used to remove the outer parasitic layer created during the porous silicon formation. We demonstrate that these etching processes influences the surface properties, in particular wetting ability. By XPS and infrared absorption spectroscopy studies, we show that a SF6 plasma treatment does not modify irreversibly the chemistry of porous silicon surface, nor the surface morphology. We also point out that NaOH etching does bring significant morphological modifications and influences the hydrophilicity of the porous silicon surface. This last treatment increases the polar groups (SiO) concentration on the pore surface and therefore allows a better filling of a porous silicon layer with organics, like dibromo-EDOT which can be thermally converted into PEDOT. 相似文献
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Fabrication of CoFe_2O_4 ferrite nanowire arrays in porous silicon template and their local magnetic properties 下载免费PDF全文
CoFe_2O_4 ferrite nanowire arrays are fabricated in porous silicon templates. The porous silicon templates are prepared via metal-assisted chemical etching with gold(Au) nanoparticles as the catalyst. Subsequently, CoFe_2O_4 ferrite nanowires are successfully synthesized into porous silicon templates by the sol–gel method. The magnetic hysteresis loop of nanowire array shows an isotropic feature of magnetic properties. The coercivity and squareness ratio(M_r/M_s) of ensemble nanowires are found to be 630 Oe(1 Oe = 79.5775 A·m~(-1) and 0.4 respectively. However, the first-order reversal curve(FORC) is adopted to reveal the probability density function of local magnetostatic properties(i.e., interwire interaction field and coercivity). The FORC diagram shows an obvious distribution feature for interaction field and coercivity. The local coercivity with a value of about 1000 Oe is found to have the highest probability. 相似文献
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采用电化学腐蚀的方法制备多孔硅。对不同实验条件下所得到的多孔硅的拉曼光谱进行了分析,确认多孔硅是具有纳米晶结构特征的材料,肯定了量子限制效应在多孔硅光致发光中的作用。 相似文献