共查询到19条相似文献,搜索用时 109 毫秒
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对多孔硅进行“胺液浸泡+快速热氧化”处理,光致发光谱显示,经处理样品的发光峰值波长短到500nm,而且在干燥空气中存放160d后,发光强度变化很小.红外吸收谱表明,处理后的多孔硅的主要成分是硅和氧,胺液没有在发蓝绿光的样品中留下残迹.电子自旋共振谱表明,这种蓝绿光样品有相当低的悬挂键密度.这些结果揭示,量子限制效应和表面态在多孔硅蓝绿光发射中起着关键性的作用.这种制备发蓝绿光样品的方法简单易行,成功率可达70%. 相似文献
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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。 相似文献
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采用化学自燃烧法制备了不同Ag+掺杂浓度的Y2O3:Eu纳米晶体粉末样品([Y3+]∶[Eu3+]∶[Ag+]=99∶1∶X,X=0—3.5×10-2),以及通过退火处理得到了相应的体材料.根据X射线衍射谱确定所得纳米和体材料样品均为纯立方相.实验表明在纳米尺寸样品中随着Ag离子浓度的增加,荧光发射强度随之增加,当X=2×10-2时达到最大值,其发光强度比X=0时提高了近50%.当Ag离子浓度继续增加,样品发光强度保持不变.在相应的体材料样品中则没有观察到此现象.通过对各样品的发射光谱,激发光谱,X射线衍射图谱,透射电镜(TEM)照片和荧光衰减曲线的研究,分析了引起纳米样品荧光强度变化的原因是由于Ag离子与表面悬键氧结合,从而使这一无辐射通道阻断,使发光中心Eu3+的量子效率提高;Ag+的引入所带来的另一个效应是使激发更为有效.这两方面原因使发光效率得到了提高. 相似文献
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光催化降解有机污染物由于其具有低能耗和绿色环保的特点,已经成为研究的热点. 氧化铋纳米晶体的带隙在2.0∽2.8 eV之间,利用它催化可见光降解有机污染物具有较高的活性,从而引起了越来越多的关注. 尽管近年来已经开发了几种制备Bi2O3基半导体材料的方法,但是仍然难以用简单的方法大规模地制备高活性的Bi2O3催化剂. 因此,开发简单可行的大规模制备Bi2O3纳米晶体的方法对于工业废水处理的潜在应用具有重要意义. 本文通过蚀刻商用BiSn粉末,然后进行热处理,成功地大规模制备了多孔Bi2O3. 获得的多孔Bi2O3在亚甲基蓝(MB)的光催化降解中表现出优异的活性和稳定性. 对该机理的进一步研究表明,多孔Bi2O3合适的能带结构允许生成活性氧物种,例如O2-·和·OH,可有效降解MB. 相似文献
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采用水热法制备了发光强度强且不衰减、峰位不蓝移的铁钝化多孔硅。标准四引线法测得的电阻一温度结果表明杂质能级是输运的主宰者;电流一电压结果说明当有电流流过样品时会有明显的热效应.考虑到金属电极和铁钝化多孔硅之间形成的肖特基势垒会对样品的输运性质产生影响,采用其平面的两引线法测量了铁钝化多孔硅样品在不同温度下的电流一电压特性,发现隧道模型可以很好地拟和这些结果这些研究结果指出作为未来的多孔硅光电集成器件;通过多孔硅的电流必须限定在一定的范围1引言 1990年英国的L.T,Canham首次成功获得在室… 相似文献
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研究了以掠入射的平面偏振光激励的多孔硅的光致发光。实验结果显示,光的入射角对多孔硅的发光行为影响不大,然而,以z方向偏振光激励的发光强度明显高于以x方向偏振光激励的发光强度。激励光电场相对于样品表面的不同取向引起光致发光的差异,这反映多孔硅的光学性质是各向异性的,也排除了纯粹的硅量子点的集合作为多孔结构的可能性。 相似文献
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Iron is incorporated in porous silicon (PS) by impregnation method using Fe(NO3)3 aqueous solution. The presence of iron in PS matrix is shown from energy-dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) measurements. The optical properties of PS and PS-doped iron are studied by photoluminescence (PL). The iron deposited in PS quenched the silicon dangling bonds then increased the PL intensity. The PL peak intensity of impregnated PS is seven times stronger than that in normal PS. Upon exposing iron-PS sample to ambient air, there is no significant change in peak position but the PL intensity increases during the first 3 weeks and then stabilises. The stability is attributed to passivation of the Si nanocrystallites by iron. 相似文献
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The interaction of porous silicon (PS) with aqueous solutions of Fe(NO3)3 with different molar (M) concentrations causes introduction of iron ions into silicon pores (PS–Fe), formation of adsorbed iron coatings with different thicknesses, and an increase in the stability of PS layers, which is important for development of device structures based of PS. To treat PS layers with solutions by the immersion method, it is necessary to determine how this affects the spectral composition and intensity of photoluminescence (PL), as well as the kinetics of PL changes during long storage under atmospheric conditions. Upon treatment of freshly prepared PS by immersion into in a Fe(NO3)3 aqueous solution, it was found that, after short-term storage (up to 5 days) of the PS samples, the PL intensity increases by 7.5 and 3–3.6 times at low (0.2 M) and high (0.7–0.8 M) concentrations of Fe(NO3)3, respectively, compared to the PL intensity of an untreated PS layer. After long-term storage (4 months), the PL intensity of PS–Fe samples with concentrations of 0.1–0.2 and 0.7–0.8 M was observed to considerably increase (by 8–18 times) with unchanged position of the PL peak with respect to untreated PS. However, at the Fe(NO3)3 concentration of 0.3 М, the PL intensity decreases and the PL peak shifts to the blue, which is explained by incomplete coverage of the PS surface by an adsorbed iron layer. The kinetics of PL spectra during long-term storage is analyzed, and a model is proposed to explain the PL intensity and spectral composition. 相似文献
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多孔硅镍钝化处理的光致发光谱研究 总被引:2,自引:0,他引:2
报道了对多孔硅在NiCl2中电解钝化处理的一种新方法,观测了经不同时间处理后多孔硅的光致发光谱,其光谱表明,恰当的处理条件,可使峰值强度增大约2.5倍,峰值波长蓝移33nm,分析了现象发生的原因是由于多孔硅表面的SiHx中的H被Ni替换成SiNix的结果。 相似文献
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InP(100) surface treated with (NH4)2Sx has been investigated by using photolumines-cence(PL), Auger electron spectroscopy and X-ray photoelectron spectroscopy, It is found that PL intensity increased by a factor of 3.3 after (NH4)2Sx passivation and the sulfur remained on the surface only bonded to indium, not to phosphorus. This suggests that the sulfur atoms replace the phosphorus atoms on the surface and occupy the phosphorus vacancies. 相似文献
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Porous silicon (PS) was passivated by silica film using a sol-gel method; the photoluminescence (PL) properties were significantly improved; namely, PL intensity and stability increased and PL peak shifted to shorter wavelength. Scanning electron microscope (SEM) and Fourier transformed infrared spectroscope (FTIR) results indicated that silica passivation produced a compact film on the PS surface and modified the surface state of PS. The number of stable surface bonds (HSiO3, HSiSiO2 and H2SiO2) increased due to the oxidation of SiH back-bonds during the gelation process, and thus the PL intensity and stability were improved. Moreover, the blue-shift of PL peak was determined due to the increase in the ratio of SiO/SiH. 相似文献
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N. Benzekkour N. Gabouze K. Ferdjani S. Sam K. Henda 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):168
In this work, we report a study on the influence of CHx thickness layer on optical properties of CHx/PS/Si structures. The hydrocarbon groups were deposited by plasma of methane–argon mixture.The properties of these structures are investigated by photoluminescence (PL), reflection and spectral response measurements from where a different behavior depending on CHx layer thickness has been observed.The entire total reflection spectrum is modulated by Fabry–Pérot fringes that are a result of thin film interference. As the CHx layer thickness increases, the amplitude of the interferences decreases and a positive shift of the maximum peak is observed.The PL spectra from CHx/PS samples with two CHx layer thicknesses show more intense luminescence than that observed from PS sample and the existence of an optimum thickness CHx that gives the maximum PL intensity. The spectral response spectra show the presence of an intense peak at 450 nm. Finally, the results point out the importance of CHx coating in optoelectronic applications. 相似文献
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Edward Sun 《Applied Surface Science》2010,256(16):5021-5223
Temperature-dependent photoluminescence (PL) from Si nanodots with Al2O3 surface passivation layers was studied. The Si nanodots were grown by low pressure chemical vapor deposition and the Al2O3 thin films were prepared by atomic layer deposition (ALD), respectively. The BOE (Buffer-Oxide-Etch) treatment resulted in the damaged surface of Si nanodots and thus caused dramatic reduction in the PL intensity. Significant enhancement of the PL intensity from Si nanodots after the deposition of Al2O3 thin films was observed over a wide temperature range, indicating the remarkable surface passivation effect to suppress the non-radiative recombination at the surface of Si nanodots. The results demonstrated that the Al2O3 surface passivation layers grown by ALD are effectually applicable to nanostructured silicon devices. 相似文献
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Zhi-qiang Xie 《Applied Surface Science》2009,255(6):3833-3836
This work demonstrates that by combining three methods with different mechanisms to enhance the photoluminescence (PL) intensity of Si nanocrystals embedded in SiO2 (or Si-nc:SiO2), a promising material for developing Si light sources, a very high PL intensity can be achieved. A 30-layered sample of Si-nc:SiO2/SiO2 was prepared by alternatively evaporating SiO and SiO2 onto a Si(1 0 0) substrate followed by thermal annealing at 1100 °C. This multilayered sample possessed a fairly high PL efficiency of 14% as measured by Greenham's method, which was 44 times that of a single-layered one for the same amount of excess Si content. Based on this multilayered sample, treatments of CeF3 doping and hydrogen passivation were subsequently applied, and a high PL intensity which was 167 times that of a single-layered one for the same amount of excess Si content was achieved. 相似文献