新型硅基蓝光材料—多孔β—SiC

硅基蓝光发射是集成化全色固态显示和光电子集成的基础材料，是发光材料研究的前沿课题。利用离子注入技术，将碳离子注入到硅中，直接形成硅基纳β－ＳｉＣ，多孔化后，由于量子限制效应，它将发射稳定的蓝光，并且可以直接制成发光图形，这是一种具有极好应用前景的硅基蓝光发射材料。     

21世纪的光学和光电子讲座第二讲 硅基发光材料和器件研究

硅基发光材料和器件是实现光电子集成的关键。文章评述了目前取得较大进展的几种主要硅基发光材料和器件的研究,包括掺饵硅,多孔硅,纳米硅以及Ｓｉ／ＳｉＯ２等超晶格结构材料,展望了这些不同硅基发光材料作为发光器件和在光电集成中的发展前景。     

21世纪的光学和光电子学讲座 第二讲 硅基发光材料和器件研究

硅基发光材料和器件是实现光电子集成的关键．文章评述了目前取得较大进展的几种主要硅基发光材料和器件的研究,包括掺饵硅,多孔硅,纳米硅以及Ｓｉ／ＳｉＯ２ 等超晶格结构材料．展望了这些不同硅基发光材料作为发光器件和在光电集成中的发展前景     

基于发光机理提高掺铒硅基材料发光效率的几条途径

掺铒硅基发光材料可以用于制备光通信用光源、光纤放大器，更重要的是可能成为实现硅基光电子集成技术的重要途径，已成为研究的热点之一．文章讨论了掺铒硅及掺铒硅基材料的发光机理，指出了制约实用化方面存在的问题．从不同方面着重探讨了共掺氧对提高掺铒硅发光效率的作用．最后介绍了基于掺铒硅发光机理提高掺铒硅基材料发光效率的几种途径、目前存在的主要问题及研究进展．     

量子点增强硅基探测成像器件的研究进展

硅基探测成像器件具有可靠性高、易集成和成本低等优点,是目前应用最广泛的探测成像器件。随着人工智能和无人驾驶等技术的日益发展,对探测成像器件提出了更高的要求,而硅基探测成像器件性能的提升成为重要的研究方向。量子点具有吸收系数大、光谱可调、发光效率高和易集成等优点,是一类优异的光谱转换和光调制材料。利用量子点材料可调制的光学特性,可以对硅基探测成像器件的功能进行拓展,从而实现紫外响应增强、红外响应拓展、紫外偏振探测和多光谱成像等功能。经过多年的研究,这一领域已经取得了一定的进展,部分技术展现出较好的应用前景。本文介绍了量子点增强硅基探测器在紫外探测、红外成像、偏振探测和多光谱成像方面的研究进展,希望能够引起国内学术界和工业界的关注和重视。     

提高Si基材料高效率发光途径的探索

近来人们对发展硅基光电子学作出了很大的努力。众所周知，如同晶体管是微电子学的核心器件一样，发光器件将是光电子学的关键部件。然而由于硅属间接带隙材料，发光效率比直接带隙的ＧａＡｓ等化合物材料低三个多量级，因此如何在硅基材料系实现高效率发光，已成为发展硅基光电子学的重要课题，它吸收着国际上众多科学、工程家们的巨大兴趣。能带工程的应用可能将提供一条有望的途径。本文总结评述了近几年来在ＳｉＧｅ量子阱能带工程，Ｅｒ３＋离子注入发光中心掺杂工程、直接带隙β—ＦｅＳｉ２材料工程以及热电子跃迁发光带内子能级工程中所取得的重要进展。本文同时对其未来的发展提出了若干设想与展望。     

多孔硅的光学非线性效应

自从1990年英国皇家信号与雷达研究所的Canham发现了多孔硅的可见光发射现象以后[1],在国际上掀起了一股多孔硅发光研究的热潮.继光致发光以后,有好几个研究组已观察到多孔硅的固态电致发光[2],这是向多孔硅在光电子器件的应用方向迈出的一大步.对于多孔硅的发光机理,虽然多数人倾向于认为这是一种量子线或量子点结构的限制效应,但也有一些与之相矛盾的实验结果,以致提出了一些其他的可能机理,如 SiH2或Si6O2H5聚合物,a-St,应变和杂质的作用等.所以要最终确定多孔硅的发光究竟是否是一种量子限制效应,还有待于提供进一步的实验事实. 另一…     

突破间接带局限创新Si基激光器

Si基高效发光与受激光发射是Si基光子学突破性发展的关键课题,它的实现对Si基微电子学的发展有深远的重大意义．由于受到天然Si材料间接带能带结构的限制,Si材料的发光效率极低,更谈不上可实现受激光发射,人工改性就成为当代研究、开拓的主要途径．新的Si基直接带体材料(如β-FeSi2等)的探索,Ge／Si量子阱、超晶格、量子点的能带工程介观改性,子带发光跃迁的探索,异类元素插入短周期超晶格中的化学键改性,以及SiO2高浓度nc-Si的生成和高激活度稀土离子的掺入发光等已开展了多途径的研究,不同程度上取得了重要的进展,一种MIS结构电子隧道注入高效发光器件已在SiO2：RE MOS结构中实现．运用激光器件物理的深入设计和新的器件技术的引入,可以预计本世纪初叶,对实现Si基激光器的奢望将会成为现实,无疑它对Si基光子学、Si基集成光电子学乃至信息高科技的发展将作出历史性的巨大贡献．     

一维光子晶体微腔在硅基材料发光中的应用研究

硅基材料的高效发光对未来硅基光电子集成的发展极其关键,含微腔的一维光子晶体可以显著提高其发光强度、窄化其发光峰.介绍了几种硅基材料发光的一维光子晶体微腔结构,包括单缺陷模式的对称与非对称结构、多缺陷模结构及电注入结构.利用传输矩阵法计算其缺陷模透射谱,以间接分析其发光谱.     

Si/SiGe量子级联激光器研究进展

Si／SiGe量子级联激光器是一种新型的带内跃迁的红外光源，突破了Si基材料间接带隙特性对光跃迁的限制。Si/SiGe量子级联激光器的开发将为实现太赫兹有源器件的硅基集成产生深远影响。文章介绍了Si/SiGe量子级联激光器的工作原理，以及这类激光器在能带设计、材料生长和波导制作方面的最新进展。     

Optimum Quantum Yield of the Light Emission from 2 to 10 nm Hydrosilylated Silicon Quantum Dots

Optimizing the light‐emitting efficiency of silicon quantum dots (Si QDs) has been recently intensified by the demand of the practical use of Si QDs in a variety of fields such as optoelectronics, photovoltaics, and bioimaging. It is imperative that an understanding of the optimum light‐emitting efficiency of Si QDs should be obtained to guide the design of the synthesis and processing of Si QDs. Here an investigation is presented on the characteristics of the photoluminescence (PL) from hydrosilylated Si QDs in a rather broad size region (≈2–10 nm), which enables an effective mass approximation model to be developed, which can very well describe the dependence of the PL energy on the QD size for Si QDs in the whole quantum‐confinement regime, and demonstrates that an optimum PL quantum yield (QY) appears at a specific QD size for Si QDs. The optimum PL QY results from the interplay between quantum‐confinement effect and surface effect. The current work has important implications for the surface engineering of Si QDs. To optimize the light‐emission efficiency of Si QDs, the surface of Si QDs must be engineered to minimize the formation of defects such as dangling bonds at the QD surface and build an energy barrier that can effectively prevent carriers in Si QDs from tunneling out.     

Investigations on AlGaN‐Based Deep‐Ultraviolet Light‐Emitting Diodes With Si‐Doped Quantum Barriers of Different Doping Concentrations

In this work, we investigate the impact of Si doped AlGaN quantum barriers on the optical powers for [0001] oriented III‐nitride based deep‐ultraviolet light‐emitting diodes (DUV LEDs). The polarization‐induced electric field in the active region is screened as the result of Si‐doped quantum barriers, which gives rise to the improved spatial overlap between electron and hole wave functions. The polarization screening effect within the quantum wells is further proven by the observation of the blue shift for the wavelength. However, the hole distribution across the active region can be significantly retarded if the Si dosage in the quantum barriers is too high. Therefore, the improved radiative recombination within the active region can be realized provided that the Si dosage in the quantum barriers is moderately adjusted to guarantee both the better hole injection efficiency and the screened polarization effect in the multiple quantum wells.     

硅衬底InGaN/GaN基蓝光发光二极管droop效应的研究

InGaN/GaN基阱垒结构LED当注入的电流密度较大时, LED的量子效率随注入电流密度增大而下降, 即droop效应.本文在Si (111)衬底上生长了 InGaN/GaN 基蓝光多量子阱结构的LED,通过将实验测量的光电性能曲线与利用ABC模型模拟的结果进行对比, 探讨了droop效应的成因.结果显示:温度下降会阻碍电流扩展和降低空穴浓度, 电子在阱中分布会越来越不平衡,阱中局部区域中因填充了势能越来越高的电子而溢出阱外, 从而使droop效应随着温度的降低在更小的电流密度下出现且更为严重, 不同温度下实验值与俄歇复合模型模拟的结果在高注入时趋势相反.这此结果表明,引起 droop效应的主因不是俄歇非辐射复合而是电子溢出,电子溢出的本质原因是载流子在阱中分布不均衡.     

Si基Ge异质结构发光器件的研究进展

近年来,与Si的CMOS工艺相兼容的Ge/Si异质结构发光器件取得很多重要的进展。本文概述了Si基Ge异质结构发光器件的最新成果,如Ge/Si量子点发光二极管、Si衬底上的Ge发光二极管及激光器和Ge/SiGe多量子阱发光二极管,分别描述了这些器件的特点和增强其发光特性的途径。最后展望了Si基Ge异质结构发光器件的发展趋势,指出尽管Si基Ge异质结构发光器件获得了很大的发展,但是器件的发光效率仍然很低,离实用还有一定距离,还需要在材料和器件的结构方面有更多的创新。     

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。     

Si quantum dot structures and their applications

This paper presents briefly the history of emission study in Si quantum dots (QDs) in the last two decades. Stable light emission of Si QDs and NCs was observed in the spectral ranges: blue, green, orange, red and infrared. These PL bands were attributed to the exciton recombination in Si QDs, to the carrier recombination through defects inside of Si NCs or via oxide related defects at the Si/SiOx interface. The analysis of recombination transitions and the different ways of the emission stimulation in Si QD structures, related to the element variation for the passivation of surface dangling bonds, as well as the plasmon induced emission and rare earth impurity activation, have been presented.The different applications of Si QD structures in quantum electronics, such as: Si QD light emitting diodes, Si QD single union and tandem solar cells, Si QD memory structures, Si QD based one electron devices and double QD structures for spintronics, have been discussed as well. Note the significant worldwide interest directed toward the silicon-based light emission for integrated optoelectronics is related to the complementary metal-oxide semiconductor compatibility and the possibility to be monolithically integrated with very large scale integrated (VLSI) circuits. The different features of poly-, micro- and nanocrystalline silicon for solar cells, that is a mixture of both amorphous and crystalline phases, such as the silicon NCs or QDs embedded in a α-Si:H matrix, as well as the thin film 2-cell or 3-cell tandem solar cells based on Si QD structures have been discussed as well. Silicon NC based structures for non-volatile memory purposes, the recent studies of Si QD base single electron devices and the single electron occupation of QDs as an important component to the measurement and manipulation of spins in quantum information processing have been analyzed as well.     

Si(110)和Si(111)衬底上制备InGaN/GaN蓝光发光二极管

分别在Si(110)和Si(111)衬底上制备了In Ga N/Ga N多量子阱结构蓝光发光二极管(LED)器件.利用高分辨X射线衍射、原子力显微镜、室温拉曼光谱和变温光致发光谱对生长的LED结构进行了结构表征.结果表明,相对于Si(111)上生长LED样品,Si(110)上生长的LED结构晶体质量较好,样品中存在较小的张应力,具有较高的内量子效率.对制备的LED芯片进行光电特性分析测试表明,两种衬底上制备的LED芯片等效串联电阻相差不大,在大电流注入下内量子效率下降较小;但是,相比于Si(111)上制备LED芯片,Si(110)上LED芯片具有较小的开启电压和更优异的发光特性.对LED器件电致发光(EL)发光峰随驱动电流的变化研究发现,由于Si(110)衬底上LED结构中阱层和垒层存在较小的应力/应变而在器件中产生较弱的量子限制斯塔克效应,致使Si(110)上LED芯片EL发光峰随驱动电流的蓝移量更小.     

p-AlGaN电子阻挡层Al组分对Si衬底绿光LED性能影响的研究

在Si(111)衬底上利用MOCVD方法生长了具有不同Al组分p-AlGaN电子阻挡层的绿光InGaN/GaN LED结构,并对其光电性能进行了研究.结果表明,不同Al组分样品的量子效率随电流密度的变化规律呈现多样性.在很低电流密度范围,LED量子效率随Al组分升高而下降;在较高电流密度范围,LED量子效率随Al组分升高而升高,即此时缓解了量子效率随电流密度增大而衰退的速率(即droop效应);但随着电流密度的进一步升高,反而加快了量子效率衰退的速率.这些现象解释为不同Al组分的p-AlGaN对空穴和电子 关键词： 氮化镓 p-AlGaN 绿光LED 量子效率     

Light emitting devices based on silicon nanostructures

In this paper, we summarize the results of an extensive investigation on the properties of MOS-type light emitting devices based on silicon nanostructures. The performances of crystalline, amorphous and Er-doped Si nanostructures are presented and compared. We show that all devices are extremely stable and robust, resulting in an intense room temperature electroluminescence (EL) at around 900 nm or at 1.54 μm. Amorphous nanostructures may constitute an interesting system for the monolithic integration of optical and electrical functions in Si ULSI technology. In fact, they exhibit an intense room temperature EL with the advantage to be formed at a temperature of only 900 °C, remarkably lower than the temperature needed for the formation of Si nanocrystals (1100 °C or higher). To improve the extraction of the light, we coupled the emitting system with a 2D photonic crystal structure properly fabricated with ULSI technology to reduce the total internal reflection of the emitted light. We demonstrate that the extraction efficiency is increased by a factor of 4. Finally, the light emission from devices based on Er-doped Si nanoclusters has been studied and in particular we have investigated the luminescence quenching processes limiting quantum efficiency in these devices. In fact the carrier injection, that determines the excitation of Er ions through electron–hole recombination, at the same time produces an efficient non-radiative Auger de-excitation with trapped carriers. These data are presented and the implications on the device performances discussed.     

Efficiency droop alleviation in blue light emitting diodes using the InGaN/GaN triangular-shaped quantum well

The InGaN/GaN blue light emitting diode(LED) is numerically investigated using a triangular-shaped quantum well model,which involves analysis on its energy band,carrier concentration,overlap of electron and hole wave functions,radiative recombination rate,and internal quantum efficiency.The simulation results reveal that the InGaN/GaN blue light emitting diode with triangular quantum wells exhibits a higher radiative recombination rate than the conventional light emitting diode with rectangular quantum wells due to the enhanced overlap of electron and hole wave functions(above 90%) under the polarization field.Consequently,the efficiency droop is only 18% in the light emitting diode with triangular-shaped quantum wells,which is three times lower than that in a conventional LED.