基于可控锗量子点的硅基微纳发光器件研究

发布时间：2018-01-01 23:05

  本文关键词：基于可控锗量子点的硅基微纳发光器件研究　出处：《华中科技大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 硅基光子学 锗量子点 图形衬底 分子束外延 光子晶体微腔 光致荧光 光学天线 锗浓缩

【摘要】：光互连是一种通过光来高速传递信息的技术,它具有高传输速率、大传输带宽等优点,因此以光互连代替电互连将是今后的一大发展趋势。硅基光互连技术因其超高传输速率、低功耗、高集成度、成熟的硅基工艺等优势,成为最有前景的下一代片上光互连方案。一个硅基光互连系统应包括硅基光源、硅基光波导、硅基调制器和硅基探测器四大核心部件。由于硅是一种间接带隙的半导体材料,发光效率低,不能为硅基集成器件提供光源。而锗自组装量子点具有易于制备、发光波长在通信波段内、与CMOS工艺兼容等优点,被认为是一种可能实现硅基发光器件的途径。量子通信网络中以单光子为量子信号的载体,从物理上保证了所传播信息的绝对安全。如果能将量子信息传输和处理所依赖的关键器件小型化、集成化,就有可能实现高速的保密通信。硅基光子芯片为高度集成化的量子信息传输和处理提供了一个良好的平台。要实现下一代硅基集成的量子信息平台,其核心课题是制备高性能的量子光源。单个锗量子点光源是一种硅基量子光源的备选方案。本论文主要围绕单个可控的锗量子点开展了一系列实验研究与理论分析,包括锗量子点的可控制备、单个锗量子点与光子晶体微腔的精确耦合、微腔增强的单个锗量子点发光等方面,具体成果可以总结为以下几个方面：(1)探索开发了锗硅材料的分子束外延生长工艺,摸索出一种“低温+高温”两步法来生长多层高密度自组装锗量子点,量子点的面密度高达9×109 cm-2。利用电子束曝光和干法刻蚀制备了大周期的硅基纳米坑图形衬底,利用分子束外延在图形衬底上生长出了低密度的定位单个锗量子点。可控的单个锗量子点在周期0.6μm～15μm的图形衬底上均能生长出来。理论分析表明量子点在纳米坑中优先成核的动力学原因是纳米坑内存在表面化学势的最小值。(2)开发了两种高精度的电子束曝光套刻标记：二氧化铪套刻标记和SOI衬底上的凹陷刻蚀标记。两种标记均能与高温工艺兼容,且对准误差均小于25nm。将电子束曝光套刻与锗量子点定位生长工艺结合起来,首次实现了硅基光子晶体微腔与单个锗量子点精确耦合器件的批量制备,量子点与微腔中心的平均对准误差为22nm。(3)系统地表征了光子晶体微腔增强的单个锗量子点的光致发光特性。在光子晶体L3腔的作用下,锗量子点出现了共振荧光增强效应；其中最强的谐振峰位于1498.8nm,增强因子约为1300。据此估算器件的Purcell因子可达66,约为已报道微腔增强锗量子点器件的10倍。单量子点与光子晶体微腔在空域和频域上的精确对准是高Purcell因子的主要原因。锗量子点在低温下较宽的荧光光谱主要来源于量子点内部复杂的复合机制,包括空穴基态的直接和间接跃迁、空穴激发态的直接和间接跃迁。测试结果表明L3腔的MO发光峰来源于微腔基模与空穴基态发光的耦合；L3腔的M3发光峰来源于微腔高阶模与空穴激发态发光的耦合。通过拟合器件的变温光谱,得到锗量子点空穴基态和激发态发光的激活能分别为151和83 meV。(4)制备并表征了金属纳米天线增强的锗量子点发光器件。设计并制作蝴蝶结金纳米天线阵列,在室温下天线对锗量子点在1577 nm处有4.2倍的发光增强。发光增强来源于天线的局域等离子体激元与附近量子点的强相互作用。依据发光增强因子及理论模拟得到的激发效率和光收集效率,可以估算出天线作用下的锗量子点的平均内量子效率提升8.09倍。(5)开发了循环高温氧化退火实现锗浓缩的工艺,提出一种结合微纳加工和锗浓缩制备可控锗硅纳米线的方案,其中所制备可控纳米线的截面特征尺寸·10 nm,合金中锗的组分高达97%。相比自组装生长的锗硅纳米线,我们制备的可控纳米线具有更好的尺寸均一性和位置可控性。作为可控锗硅纳米线的应用,我们设计并制作了一系列基于可控锗硅纳米线的光电导探测器。
[Abstract]:Optical interconnection is a kind of light through the high-speed transmission of information technology, it has high transmission rate, large transmission bandwidth advantages, so the optical interconnection instead of electrical interconnection will be a major trend in the future. Silicon based optical interconnection technology due to its high transmission rate, low power consumption, high integration, silicon technology the advantages of mature and become the next generation of on-chip optical interconnection scheme. One of the most promising silicon-based optical interconnection system comprises a silicon light source, optical waveguide based on silicon, silicon and silicon modulator detector four core components. Because silicon is a semiconductor material with an indirect band gap, low luminous efficiency that cannot provide a source for silicon and germanium integrated devices. Self assembled quantum dots has the advantages of easy preparation, the wavelength of the light in the communication range, and the advantages of CMOS process compatible, is considered a possible realization of silicon-based light-emitting devices. Quantum communication network with single photon quantity The sub carrier signal, absolutely safe from the physical to ensure the dissemination of information. If they can be miniaturized, quantum information transmission and processing on the key components of integration, it is possible to achieve secure communication. High speed silicon photonic chip for quantum information integrated transmission and provides a good the platform to realize quantum information processing. An integrated platform for the next generation of silicon, the core issue is the preparation of high performance light quantum. Single germanium quantum dots is an alternative to a light silicon based quantum light source. This thesis mainly focuses on a single controllable germanium content sub points to carry out the experimental study and theoretical analysis of a the series, including the controlled preparation of Ge quantum dots, precise coupling single germanium quantum dots and photonic crystal microcavity, single germanium quantum dot microcavity enhanced luminescence etc., concrete results can be summarized as follows: (1) exploration The development of molecular beam epitaxy of silicon germanium material technology, develop a "low temperature and high temperature" two step growth of multilayer high density self-assembled germanium quantum dots, quantum dots surface density of up to 9 x 109 cm-2. silicon nano pit patterned substrate period using electron beam lithography and dry etching preparation and on a patterned substrate were grown by positioning a single low density germanium quantum dots by molecular beam epitaxy. Single germanium quantum dots grown in controlled cycle of 0.6 m to 15 m on the patterned substrate can. Theoretical analysis shows that the quantum dots in nano pits preferentially into the dynamic cause of nuclear is minimum the existence of surface chemical potential of nano pits. (2) developed two kinds of high precision electron beam exposure etching mark: two hafnium oxide etching etching mark and depression on the SOI substrate. The two markers were compatible with the high temperature process, and the alignment error is less than 25N M. electron beam exposure etching and germanium quantum dots growth positioning technology combine for the first time to realize the accurate coupling device of silicon photonic crystal microcavity with single Ge quantum dots preparation, quantum dots and the cavity center average alignment error is 22nm. (3) system to characterize the luminescence properties of single germanium quantum the point of photonic crystal microcavity enhanced light in photonic crystal L3 cavity under the action of Ge quantum dots appear resonance fluorescence enhancement effect; the strongest resonance peak at 1498.8nm, the enhancement factor is about 1300. estimated Purcell factor is about 66 devices, has been reported in micro cavity enhanced 10 times germanium quantum dot devices the single quantum dots and photonic crystal microcavity in spatial domain and frequency domain of the precise alignment is the main reason for the high Purcell factor. The fluorescence spectra of Ge quantum dots at low temperature, wide mainly comes from the composite mechanism of complex internal quantum dots, Including direct and indirect transition of the ground state hole, direct and indirect transition hole excited state. The test results show that the L3 cavity of the MO emission peak from coupled microcavity mode and the light hole ground state; L3 cavity M3 emission peak from the micro cavity with high order coupling hole excitation state. The temperature dependent luminescence spectral fitting the device, get germanium quantum dots emitting hole ground and excited states of activation energy were 151 and 83 meV. (4) Ge quantum dots preparation and characterization of metal nano antenna enhanced luminescence device. Making bows of gold nano antenna array design and, at room temperature on the antenna of Ge quantum dots luminescence enhanced 4.2 times at 1577 nm. The localized plasmon enhanced photoluminescence from the antenna and near the quantum dots of the strong interaction. On the basis of the luminescence enhancement factor and the theory of simulated excitation efficiency and light collection efficiency, we can estimate the antenna The average of Ge quantum dots under the effect of internal quantum efficiency 8.09 times. (5) developed a cyclic high temperature oxidation annealing process of germanium concentration, proposes a combination of controlled synthesis of silicon germanium nanowires micromachining and germanium concentration solution, the preparation of controlled nanowires with feature size - 10 nm alloy germanium component, up to 97%. compared to silicon germanium nanowires self-assembly, we prepared nanowires prepared has better controllable size uniformity and controllability of application. As the controllable germanium silicon nanowires, we designed and produced a series of controllable germanium photoconductive detector based on silicon nanowires.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN36;O734
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本文编号：1366584