本文關(guān)鍵詞：氮化鎵（GaN）表面微納米結(jié)構(gòu)在界面改性和光電探測領(lǐng)域中的應(yīng)用　出處：《山東大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： GaN極性 金屬局域等離激元 Comsol有限元仿真 表面潤濕性 光電響應(yīng)

【摘要】：信息和能源技術(shù)的發(fā)展離不開半導(dǎo)體材料及高效率光電轉(zhuǎn)換器件。以氮化鎵(GaN)為代表的寬帶隙半導(dǎo)體具有禁帶寬度大,電子飽和漂移速度高、介電常數(shù)小、擊穿場強大、導(dǎo)電導(dǎo)熱性能好的特點,在國防、通訊、能源、照明、新能源汽車、智能電網(wǎng)等諸多領(lǐng)域均有極大的需求,是國際各國競相發(fā)展的重要研究方向。基于以上研究背景,本論文深入研究GaN表面結(jié)構(gòu)的制備方法,結(jié)合金屬局域等離激元納米結(jié)構(gòu),實現(xiàn)了 GaN表面潤濕性能的調(diào)控;發(fā)現(xiàn)了 n型GaN的紫外光致親水行為并證明其與GaN表面的雜質(zhì)氧有關(guān);結(jié)合有限元仿真分析方法,發(fā)現(xiàn)了 GaN的極化電場可以大幅度提高熱電子的注入效率,從而有效提高了光電探測效率。本論文的正文部分共有五章,分別是第一章緒論;第二章GaN表面微納米結(jié)構(gòu)的制備及局域等離激元光學(xué)性質(zhì)的仿真;第三章GaN表面微納米結(jié)構(gòu)對潤濕性能的調(diào)控;第四章GaN表面微納米結(jié)構(gòu)對光電探測性能的調(diào)控;第五章結(jié)論與展望。主要研究內(nèi)容和結(jié)論包括:第一章:細致闡述和分析了 GaN材料結(jié)構(gòu)特征、物理性質(zhì)及表面微納米結(jié)構(gòu)的制備方法,在此基礎(chǔ)上,進一步詳細綜述了材料表面潤濕性和半導(dǎo)體光電探測原理。第二章:1、研究了不同極性GaN表面腐蝕結(jié)構(gòu)的制備方法及其反應(yīng)機制。結(jié)論包括:(1)實現(xiàn)了 Ga極性GaN表面的無外加氧化劑腐蝕并研究了其腐蝕機制,發(fā)現(xiàn)在紫外光照下Au催化產(chǎn)生的羥基自由基可以實現(xiàn)GaN的氧化。(2)在N極性GaN表面利用KOH制備了金字塔狀的腐蝕結(jié)構(gòu)并研究了K2S208對腐蝕結(jié)構(gòu)的影響。2、應(yīng)用光化學(xué)法和濺射退火法實現(xiàn)了 Au、Ag納米顆粒結(jié)構(gòu)的制備并研究了其反應(yīng)動力學(xué)特征。結(jié)論包括:(1)對于光化學(xué)法生長Au納米顆粒,隨著光照時間的延長,顆粒尺寸增大,密度增加。當(dāng)光照時間為10min時,顆粒的平均粒徑為～128.7nm,顆粒密度為～18.3/μ2。(2)在濺射退火法制備過程中,對于Au納米顆粒,增加濺射時間和升高退火溫度均可增加顆粒尺寸,降低顆粒密度。對于Ag納米顆粒,增加濺射時間反而會減小顆粒尺寸,增加顆粒密度,而退火溫度對納米顆粒尺寸的影響不明顯。3、利用Comsol Multiphysics有限元軟件模擬仿真了金屬納米顆粒局域等離激元共振特征及其近場光學(xué)性質(zhì)。結(jié)論包括:(1)Au納米顆粒尺寸增大會導(dǎo)致光散射增強和局域等離激元共振峰紅移。對處于空氣中的Au納米顆粒來說,當(dāng)半徑從5nm增加至50nm時,局域等離激元共振峰會有20nm的紅移。顆粒越小,其周圍電場強度越大。半徑為5nm的Au顆粒其周圍電場強度約是半徑為50nm顆粒的103倍。(2)納米顆粒周圍介質(zhì)折射率的增大會使光散射增強。對于GaN中半徑為25nm的Au納米顆粒,其局域等離激元共振處的光散射大于光吸收。而且,折射率大的介質(zhì)會使等離激元共振峰產(chǎn)生明顯紅移,對半徑為25nm處于GaN中的Au納米顆粒,其共振峰要比在空氣中時紅移120nm。第三章:1、研究了 GaN的Ga面和N面微納米結(jié)構(gòu)對潤濕行為的影響。結(jié)論包括:(1)Ga極性面和N極性面微納米結(jié)構(gòu)會使GaN更親水,其中Ga極性面接觸角最小可達21.8°,N極性面最小可達42.1°,月桂酸修飾后微納米結(jié)構(gòu)會使GaN更疏水,其中Ga極性面接觸角最大可達138.5°,N極性面最大可達129.5°。(2)Ga極性和N極性GaN經(jīng)月桂酸修飾后的微納米結(jié)構(gòu)表面可表現(xiàn)出高表面粘滯性。Ga極性GaN的前進和后退接觸角之差最大可達40°,而N極性GaN可達 50°。2、研究了紫外輻照對GaN表面潤濕性的影響。結(jié)論包括:(1)紫外輻照可導(dǎo)致n型GaN的接觸角從原61.3°變至10°左右,且黑暗環(huán)境下放置可使接觸角回復(fù)至初始狀態(tài)。而上述過程對p型GaN則沒有影響。(2)n型GaN具有紫外光致親水性與表面雜質(zhì)氧的減少有關(guān),水分子在氧空位處進行解離吸附所形成的羥基基團使接觸角大大降低;而p型GaN中由于氧含量低而不存在該過程。(3)n型GaN在表現(xiàn)出紫外光致親水行為的同時,其光致發(fā)光譜中黃光帶的發(fā)光強度大大增加,這是由于表面能帶結(jié)構(gòu)彎曲程度和耗盡層寬度的減小使輻射復(fù)合幾率增大引起的,而p型GaN則沒有該現(xiàn)象。第四章:1、研究了 CaN腐蝕結(jié)構(gòu)對光電探測性能的調(diào)控。結(jié)論包括:GaN腐蝕后其光電流約是空白樣品的1.65倍。在365nm處的光譜響應(yīng)靈敏度約是空白樣品的1.5倍,腐蝕后的樣品響應(yīng)時間比空白樣品小。2、利用三明治結(jié)構(gòu)的Au-Cu20驗證了金屬局域等離激元的光學(xué)性質(zhì)對半導(dǎo)體光電探測性能的提高。結(jié)論包括:(1)電化學(xué)沉積過程中,Cu20的成核過程屬于瞬時爆發(fā)成核。(2)Au納米顆�？梢允笴u20光電探測器的光暗電流比提高199.7%(約是空白樣品的3倍),光電轉(zhuǎn)換效率提高54.3%。3、研究了 GaN的極性對金屬納米顆粒局域等離激元調(diào)控半導(dǎo)體光電探測性能的影響。結(jié)論包括:(1)金屬納米顆粒可以大大提高GaN的光電探測性能,其中Au納米顆�？梢允笹aN的光譜響應(yīng)靈敏度在紫外和綠光部分分別是空白樣品的54倍和64倍,而Ag納米顆粒僅在紫外部分使GaN的光譜響應(yīng)靈敏度提高,約是空白樣品的18倍。(2)有限元仿真計算表明Au納米顆粒增加的光吸收僅可使GaN的光譜響應(yīng)靈敏度在紫外和綠光部分分別提高約4.4和3.1倍。該結(jié)果與N極性GaN上所測結(jié)果一致,但是卻遠遠小于Ga極性GaN上測得的結(jié)果。(3)GaN極化場在促進熱電子注入方面扮演了十分重要的角色。Ga極性GaN在紫外部分的高響應(yīng)來源于極化場促進了熱電子的注入;而在綠光部分的提高來源于局域等離激元共振時促進的缺陷電離。綜上所述,我們在GaN上實現(xiàn)了腐蝕結(jié)構(gòu)和金屬納米顆粒的制備,利用有限元仿真分析了金屬納米顆粒局域等離激元的光學(xué)性質(zhì),進而研究了上述兩種表面微納米結(jié)構(gòu)對GaN表面潤濕性能和光電探測性能的調(diào)控機制,最后結(jié)合有限元仿真結(jié)果和實驗結(jié)果分析了 GaN極性在金屬納米顆粒局域等離激元調(diào)控GaN光電探測性能上的影響。本論文的創(chuàng)新之處在于(1)研究了 GaN光化學(xué)腐蝕特性,實現(xiàn)了 Ga極性GaN的無外加氧化劑腐蝕。研究了不同極性GaN表面的潤濕行為并制備了疏水且具有高粘附性的GaN表面。(2)發(fā)現(xiàn)了 n型GaN的紫外光致親水轉(zhuǎn)變并證明其與GaN表面的雜質(zhì)氧有關(guān)。(3)制備了等離激元半導(dǎo)體(Au-Cu2O)三明治結(jié)構(gòu)并驗證了利用局域等離激元提高半導(dǎo)體光電探測性能的可能性。(4)利用Au納米顆粒局域等離激元效應(yīng)實現(xiàn)了 GaN在紫外和綠光部分光譜響應(yīng)靈敏度大幅度提升,證明了 GaN極化場有促進熱電子注入的作用。
[Abstract]:The development of information technology and energy cannot do without semiconductor materials and high efficiency photoelectric converter. Using gallium nitride (GaN) as the representative of the wide band gap semiconductor with wide band gap, high electron saturation drift velocity, low dielectric constant, breakdown field strength, good thermal conductivity properties of the special point in national defense, communications, energy, lighting smart grid, new energy vehicles, and many other areas of great demand, is an important research direction in the international countries. Based on the above research background, this paper studies GaN surface structure preparation method, node metal localized plasmonic nanostructures with controlled GaN surface wettability was found; N type GaN ultraviolet light induced hydrophilic behavior and prove its related impurity oxygen GaN surface; combined with finite element analysis method, found the GaN polarization electric field can improve the efficiency of injected hot electrons substantially, from And effectively improve the photoelectric detection efficiency. Part of the body of this paper consists of five chapters. Chapter I is introduction; simulation of plasmonic optical properties of second GaN surface micro nano structure preparation and local regulation; the third chapter GaN surface micro nano structure on the wetting properties; the fourth chapter GaN surface micro regulation the nano structure of the photoelectric detection performance; the fifth chapter is conclusion and prospect. The main research contents and conclusions include: the first chapter: the detailed description and analysis of the structure characteristics of GaN material, preparation method of micro nano structure and physical properties of the surface, on this basis, further detailed review of the principle of surface wettability of material and semiconductor photoelectric detection. The second chapter: 1, study the different polar GaN surface corrosion structure preparation method and reaction mechanism. The conclusions include: (1) achieved without additional oxidant corrosion and its corrosion Ga polar GaN surface For that, the hydroxyl radical oxidation under UV Irradiation Catalyzed by Au can achieve GaN. (2) N in the polar GaN surface using KOH for corrosion structure Pyramid like prepared and studied the effect of K2S208 on corrosion structure of.2 by photochemical method and sputtering annealing method to achieve the Au, Ag nanoparticles the preparation and study of its reaction kinetics. The conclusions include: (1) for photochemical growth of Au nanoparticles, with the illumination time is prolonged, the increase of the particle size, the density increased. When the illumination time is 10min, the average size of the particles is ~ 128.7nm, 18.3/ ~ 2. mu of grain density (2) in the preparation of sputtering and annealing process for Au nanoparticles, increase the sputtering time and the annealing temperature can increase the particle size, particle density decreases. For Ag nanoparticles, increase the sputtering time but will reduce the particle size, the particle density increases, and back Effect of annealing temperature on the nano particle size was.3, the simulation of metal nanoparticles localized plasmon resonance characteristics and near-field optical properties by using Comsol finite element software Multiphysics. The conclusions include: (1) Au nano particle size increases will lead to light scattering enhancement and localized plasmon resonance peak of red shift. In the Au nano particles in the air, when the radius is increased from 5nm to 50nm, and other local 20nm plasmon resonance redshift summit. The smaller the particle is, the greater the field strength. Around the radius of Au 5nm particles around the field strength is about 103 times the radius of 50nm particles (2). Nano particles of the refractive index increases with light scattering enhancement. The GaN radius of Au nano particles 25nm, light scattering from the plasmon resonance of the localization is greater than the light absorption and refractive index of the medium will make the plasmon resonance peak. 鐢熸槑鏄劇孩縐，

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