本文關鍵詞：基于可控鍺量子點的硅基微納發(fā)光器件研究　出處：《華中科技大學》2016年博士論文　論文類型：學位論文

  更多相關文章： 硅基光子學 鍺量子點 圖形襯底 分子束外延 光子晶體微腔 光致熒光 光學天線 鍺濃縮

【摘要】：光互連是一種通過光來高速傳遞信息的技術,它具有高傳輸速率、大傳輸帶寬等優(yōu)點,因此以光互連代替電互連將是今后的一大發(fā)展趨勢。硅基光互連技術因其超高傳輸速率、低功耗、高集成度、成熟的硅基工藝等優(yōu)勢,成為最有前景的下一代片上光互連方案。一個硅基光互連系統(tǒng)應包括硅基光源、硅基光波導、硅基調制器和硅基探測器四大核心部件。由于硅是一種間接帶隙的半導體材料,發(fā)光效率低,不能為硅基集成器件提供光源。而鍺自組裝量子點具有易于制備、發(fā)光波長在通信波段內、與CMOS工藝兼容等優(yōu)點,被認為是一種可能實現(xiàn)硅基發(fā)光器件的途徑。量子通信網(wǎng)絡中以單光子為量子信號的載體,從物理上保證了所傳播信息的絕對安全。如果能將量子信息傳輸和處理所依賴的關鍵器件小型化、集成化,就有可能實現(xiàn)高速的保密通信。硅基光子芯片為高度集成化的量子信息傳輸和處理提供了一個良好的平臺。要實現(xiàn)下一代硅基集成的量子信息平臺,其核心課題是制備高性能的量子光源。單個鍺量子點光源是一種硅基量子光源的備選方案。本論文主要圍繞單個可控的鍺量子點開展了一系列實驗研究與理論分析,包括鍺量子點的可控制備、單個鍺量子點與光子晶體微腔的精確耦合、微腔增強的單個鍺量子點發(fā)光等方面,具體成果可以總結為以下幾個方面：(1)探索開發(fā)了鍺硅材料的分子束外延生長工藝,摸索出一種“低溫+高溫”兩步法來生長多層高密度自組裝鍺量子點,量子點的面密度高達9×109 cm-2。利用電子束曝光和干法刻蝕制備了大周期的硅基納米坑圖形襯底,利用分子束外延在圖形襯底上生長出了低密度的定位單個鍺量子點�？煽氐膯蝹�鍺量子點在周期0.6μm～15μm的圖形襯底上均能生長出來。理論分析表明量子點在納米坑中優(yōu)先成核的動力學原因是納米坑內存在表面化學勢的最小值。(2)開發(fā)了兩種高精度的電子束曝光套刻標記：二氧化鉿套刻標記和SOI襯底上的凹陷刻蝕標記。兩種標記均能與高溫工藝兼容,且對準誤差均小于25nm。將電子束曝光套刻與鍺量子點定位生長工藝結合起來,首次實現(xiàn)了硅基光子晶體微腔與單個鍺量子點精確耦合器件的批量制備,量子點與微腔中心的平均對準誤差為22nm。(3)系統(tǒng)地表征了光子晶體微腔增強的單個鍺量子點的光致發(fā)光特性。在光子晶體L3腔的作用下,鍺量子點出現(xiàn)了共振熒光增強效應；其中最強的諧振峰位于1498.8nm,增強因子約為1300。據(jù)此估算器件的Purcell因子可達66,約為已報道微腔增強鍺量子點器件的10倍。單量子點與光子晶體微腔在空域和頻域上的精確對準是高Purcell因子的主要原因。鍺量子點在低溫下較寬的熒光光譜主要來源于量子點內部復雜的復合機制,包括空穴基態(tài)的直接和間接躍遷、空穴激發(fā)態(tài)的直接和間接躍遷。測試結果表明L3腔的MO發(fā)光峰來源于微腔基模與空穴基態(tài)發(fā)光的耦合；L3腔的M3發(fā)光峰來源于微腔高階模與空穴激發(fā)態(tài)發(fā)光的耦合。通過擬合器件的變溫光譜,得到鍺量子點空穴基態(tài)和激發(fā)態(tài)發(fā)光的激活能分別為151和83 meV。(4)制備并表征了金屬納米天線增強的鍺量子點發(fā)光器件。設計并制作蝴蝶結金納米天線陣列,在室溫下天線對鍺量子點在1577 nm處有4.2倍的發(fā)光增強。發(fā)光增強來源于天線的局域等離子體激元與附近量子點的強相互作用。依據(jù)發(fā)光增強因子及理論模擬得到的激發(fā)效率和光收集效率,可以估算出天線作用下的鍺量子點的平均內量子效率提升8.09倍。(5)開發(fā)了循環(huán)高溫氧化退火實現(xiàn)鍺濃縮的工藝,提出一種結合微納加工和鍺濃縮制備可控鍺硅納米線的方案,其中所制備可控納米線的截面特征尺寸·10 nm,合金中鍺的組分高達97%。相比自組裝生長的鍺硅納米線,我們制備的可控納米線具有更好的尺寸均一性和位置可控性。作為可控鍺硅納米線的應用,我們設計并制作了一系列基于可控鍺硅納米線的光電導探測器。
[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.

【學位授予單位】：華中科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TN36;O734
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本文編號：1366584