共查询到18条相似文献,搜索用时 62 毫秒
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利用热蒸发技术在硅衬底上制备了层厚不同的SiO/SiO2超晶格样品.对其光致发光谱进行研究发现,随着SiO/SiO2超晶格中SiO层厚度的增加,发光峰在400~600 nm之间移动.研究表明,样品的发光中心来自于SiO/SiO2界面处的缺陷发光(界面态发光).即在样品沉积的过程中,在SiO/SiO2的界面处由于晶格的不连续性,会形成大量的Si-O悬挂键,这些悬挂键本身相互结合可以形成一定数量的缺陷,同时由于O原子容易脱离Si原子的束缚而产生扩散,因此,这些悬挂键可以与扩散的O原子结合,随着SiO层厚度的增加,在SiO/SiO2的界面处先后出现WOB(O3<≡Si-O-O·),NOV(O3≡Si-Si≡O3),E'中心(O≡Si·),NBOHC(O3≡Si-O·)等缺陷,这些缺陷在SiO层厚度增大的过程中对发光先后起到主导作用,从而使得发光峰产生红移. 相似文献
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用磁控溅射方法在玻璃基底上制备了非晶Si/SiO2超晶格.利用透射电子显微镜 (TEM) 和X射线衍射技术对其结构进行了分析,结果表明,超晶格中Si层大部分区域为非晶相,局域微区呈现有序结构,其厚度由1.8—3.2nm变化,SiO2层厚度为4.0nm.并采用多种光谱测量技术,如吸收光谱、光致发光光谱和Raman光谱技术,对该结构的光学性质进行了系统研究.结果表明,随纳米Si层厚度的减小,光学吸收边以及光致荧光峰发生明显蓝移,Raman峰发生展宽,即观测到明显的量
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Si Ge量子阱和超晶格的光发射 总被引:3,自引:0,他引:3
系统地介绍了近几年来国内外对SiGe量子阱及短周期超晶格光发射的研究现状。由于Si,Ge材料及器件在微电子学领域内的无可比拟的优越性,所以,超过90%的芯片技术是Si基的,然而,由于Si,Ge是间接带隙,载流子跃迁几率小,其光电应用受到很大的限制,为此,人们作出了不懈的努力,并取得了可喜的进展。 相似文献
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研究了具有InGaN/GaN超晶格(SL)插入结构的绿光InGaN/GaN多量子阱(MQW)的发光特性。结构测试表明,SL插入结构并没有引起MQW中平均In组份的增加,而是改变了In组份的分布,形成了高In组份的量子点和低In组份量子阱。其电致发光(EL)谱和光致发光(PL)谱均出现了双发光峰。我们认为这两个 峰分别来自于量子点和量子阱,且存在着载流子从阱向点转移的输运机制。最后变温PL积分强度的Arrhenius 拟合表明,SL插入结构并没有在MQW中引入新的缺陷,使其发光效率下降。 相似文献
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Si基异质结构与应用前景 总被引:1,自引:0,他引:1
综述了90年代以来SiGe/Si等Si基异质结构材料的优异特性的诱人的应用前景,着重介绍了能带工程为Si基异质结构带来的新特性、新功能。 相似文献
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W. XuH.C. Sun J. Xu W. LiW.W. Mu Y. LiuM.Y. Yan X.F. HuangK.J. Chen 《Applied Surface Science》2011,258(1):346-349
We report the fabrication of Si quantum dots (QDs)/SiO2 multilayers by using KrF excimer laser (248 nm) crystallization of amorphous Si/SiO2 multilayered structures on ITO coated glass substrates. Raman spectra and transmission electron microscopy demonstrate the formation of Si QDs and the size can be controlled as small as 1.8 nm. After laser crystallization, Al electrode is evaporated to obtain light emitting devices and the room temperature electroluminescence (EL) can be detected with applying the DC voltage above 8 V on the top gate electrode. The luminescent intensity increases with increasing the applied voltage and the micro-watt light output is achieved. The EL behaviors for samples with different Si dot sizes are studied and it is found that the corresponding external quantum efficiency is significantly enhanced in sample with ultra-small sized Si QDs. 相似文献
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Light Harvesting and Enhanced Performance of Si Quantum Dot/Si Nanowire Heterojunction Solar Cells 下载免费PDF全文
Yunqing Cao Zhaoyun Ge Xiaofan Jiang Jun Xu Ling Xu Wei Li Linwei Yu Kunji Chen 《Particle & Particle Systems Characterization》2016,33(1):38-43
Si nanowires (Si NWs) structures with good antireflection and enhanced optical‐absorption properties are used to fabricate Si quantum dots/Si NWs heterojunction solar cells. The Si NWs prepared by the metal‐assisted chemical‐etching technique exhibit a very low reflection in a wide spectral range (300–1200 nm). Correspondingly, the optical absorption reaches as high as 88.9% by weighting AM1.5G solar spectrum. Both the short current density and open current voltage are improved compared to the reference flat cell. However, the photovoltaic properties are degraded by varying the Si NWs with long etching time, possibly due to the increased etching‐induced surface states. The optimal Si NWs lead to the best cell with the power conversion efficiency of 11.3%. 相似文献
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Si/Ge应变层超晶格的椭偏光谱 总被引:2,自引:0,他引:2
测量了几种不同组分的(Si)M/(Ge)N应变超晶格材料的椭偏光谱(2.0~5.0eV),并得到了其介电函数谱;应用介电函数的临界点理论,研究了(Si)M/(Ge)N应变超晶格材料的光学性质。发现短周期Si/Ge应变超晶格除了具有明显的E1和E2带间跃迁外,还存在与应力和超晶格能带的折迭效应有关的跃迁峰,其能量分别位于2.3~3.0eV和3.3~4.0eV范围内 相似文献
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D. J. Paul S. A. Lynch R. Bates Z. Ikonic R. W. Kelsall P. Harrison D. J. Norris S. L. Liew A. G. Cullis P. Murzyn C. Pidgeon D. D. Arnone D. J. Robbins 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):309
Intersubband electroluminescence results are presented from Si/SiGe quantum cascade emitters at 3.2 THz and at temperatures up to 150 K. The effect of adding doping into the active quantum wells was studied in addition to reduced barrier widths from previous measurements. While the current through the sample is increased by the addition of doping, the emitted power is reduced through additional free carrier absorption and Coulombic scattering. Free electron laser measurements confirm the intersubband transitions in the quantum wells of the cascade devices and produce non-radiative lifetimes of 20 ps between 4 and 150 K. 相似文献