GaN和Al_xGa_(1-x)N薄膜材料研究进展

ＧａＮ及ＡｌｘＧａ１－ｘＮ是发兰光的关键材料，是目前光电子材料中最引人注目、必须攻克的课题。本文综述了ＧａＮ及ＡｌｘＧａ１－ｘＮ材料的研究现状，重点介绍了ＧａＮ及ＡｌｘＧａ１－ｘＮ材料近年来在性能评价、生长技术和应用开发方面的进展     

GaN和AlxGa1—xN薄膜材料研究进展

ＧａＮ及ＡｌｘＧａ１－ｘＮ是发兰光的关键材料，是目前光电子材料中最引人注目，必须攻克的课题。本文综述了ＧａＮ及ＡｌｘＧａ１－ｘＮ材料的研究现状重点介绍了ＧａＮ及ＡｌｘＧａ１－ｘＮ材料近年来在性能评价，生长技术和应用开发方面的进展。     

Γ-含幺半群和Γ-群

给出了Γ－含幺半群的概念和研究了它的构造。证明了Γ－含幺半群的结构被它的任一确定的相关半群Ｍα及Ｍα的幺元素的特性唯一确定，对Γ－群给出了如下结果：设Ｇ是群和Γ是Ｇ的任一确定的非空子集，对ａ，ｂ∈Ｇ和α∈Γ，若规定ａαｂ为元素ａ，α和ｂ在Ｇ中的积。则Ｇ是Γ－群，反之，任一Γ－群必同构于用上述方法构造的某一Γ－群。     

δ－掺杂GaAs／AlxGa_（1－x）As二维电子气结构材料的GSMBE生长与特性

本文用ＧＳＭＢＥ技术生长纯度ＧａＡｓ和δ－掺杂ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ结构二维电子气材料并对其电学性能进行了研究。对于纯度ＧａＡｓ的ＧＳＭＢＥ生长和研究，在低掺Ｓｉ时，载流子浓度为２×１０~（１４）ｃｍ~（－３），７７Ｋ时的迁移率可达８４，０００ｃｍ~２／Ｖ．ｓ。对于用ＧＳＭＢＥ技术生长的δ－掺杂ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ二维电子气材料，在优化了材料结构和生长工艺后，得到了液氮温度和６Ｋ迁移率分别为１７３，５８３ｃｍ~２／Ｖ．５和７．６７×１０~５ｃｍ~２／Ｖ．ｓ的高质量ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ二维电子气材料。     

GaAs Mach－Zehnder型光波导开关／调制器

采用非对称Ｘ结耦合器代替传统的Ｙ分支器，研制了ＧａＡｓＭａｃｈ－Ｚｅｈｎｄｅｒ型２×２光开光，得到了小于－２２．４ｄＢ的串音比和１２Ｖ左右的开关电压，器件的波导传输损耗小于７ｄＢ／ｃｍ。预计该器件可广泛应用于ＧａＡｓ开关列阵及高速光调制等领域。     

纳米GaAs—SiO2镶嵌复合薄膜的制备

利用射频磁控共溅法制备了纳米ＧａＡｓ－ＳｉＯ２镶嵌复合薄膜，通过Ｘ射线衍射，透射电镜和Ｘ射线光电子能谱等手段研究了薄膜的结构及其与沉积时基片温度间的关系，结果表明，薄膜由晶态的ＧａＡｓ及非晶ＳｉＯ２组成，ＧａＡｓ在沉积过程中未明显氧化，且以纳米颗粒形成的均匀地弥散在ＳｉＯ２中；ＧａＡｓ的平均粒径依赖于沉积时的基片温度，获得了ＧａＡｓ的平均粒径在３～１０ｎｍ的ＧａＡｓ→ＳｉＯ２镶嵌复合薄膜。     

SI—GaAs中的EL2和EL6缺陷团簇相关性研究

用光致电流瞬态谱（ＰＩＴＳ）方法研究了ＬＥＣＳＩ－ＧａＡｓ原生单晶经常规退火和等时快速退火（ＲＴＡ）深能级缺陷的变化。缺陷ＥＬ２（Ｅｃ－０．８２ｅＶ）ＥＬ１２（Ｅｃ－０．７９ｅＶ）表现出类似的ＲＴＡ特性，应属于ＥＬ２缺陷团簇；缺陷ＥＬ６（Ｅｃ－０．３８ｅＶ），ＥＬ８（Ｅｃ－０．２７ｅＶ）和ＥＬ９（Ｅｃ－０．２４ｅＶ０亦具有相似的ＲＴＡ特性，属ＥＬ６缺陷团簇。实验发现，在热退火中，ＥＬ２团簇缺陷密度     

纳米GaAs—SiO镶嵌复合薄膜的发光特性

采用射频磁控共溅射法制备了纳米ＧａＡｓ－ＳｉＯ２镶嵌复合薄膜。通过Ｘ射线衍射、透射电镜观察和Ｘ射线光电子能谱等手段研究了薄膜的结构及其与沉积过程中基片温度间的关系。测量了薄膜的光致发光特性。表明，薄膜由晶态的ＧａＡｓ及非晶Ｓdisplay status两相组成，ＧａＡｓ在沉积过程中未明显氧化且以纳米颗粒形式均匀地弥散；ＧａＡｓ的平均粒径依赖于沉积时的基片温度。通过控制基片温度，成功地获得了ＧａＡｓ的平均粒径分     

n型GaSb,InGaAsSb的MBE生长和特性研究

本文报导了非故意掺杂ＩｎＧａＡｓＳｂ本底浓度的降低和掺Ｔｅｎ型ＧａＳｂ和ＩｎＧａＡｓＳｂ的ＭＢＥ生长与特性的研究结果。结果表明，通过生长工艺的优化，ＧａＳｂ和ＩｎＧａＡｓＳｂ的背景空穴浓度可分别降至１．１×１０~（１６）ｃｍ~（－３）和４×１０~（１６）ｃｍ~（－３），室温空穴迁移率分别为９４０ｃｍ２／ｖ．ｓ和２６０ｃｍ~２／ｖ．ｓ。用Ｔｅ作ｎ型掺杂剂，可获得载流子浓度在１０~（１６）～１０~（１８）ｃｍ~（－３）的优质ＧａＳｂ和ＩｎＧａＡｓＳｂ外延层，所研制的材料已成功地制备出Ｄ_λ~＊＝４×１０~（１０）ｃｍＨｚ~（１／２）／Ｗ的室温ＩｎＧａＡｓＳｂ红外探测器和室温脉冲ＡｌＧａＡｓＳｂ／ＩｎＧａＡｓＳｂ双异质结激光器。     

Ga－Al－As－Si系统中Si的两性掺杂行为的研究

对Ｓｉ在电液相外延Ｇａ－Ａｌ－Ａｓ－Ｓｉ系统中的两性掺杂行为进行了研究。提出了一种恒温生长Ｇａ＿（１－ｘ）Ａｌ＿ｘＡｓ：Ｓｉｐ－ｎ结的新方法，对这种ｐ－ｎ结的成因作了定性的解释，并对这种ｐ－ｎ结的电特性加以观察。     

Solid-state gallium NMR characterization of cubic gallium nitride prepared by the reaction of gallium arsenide with ammonia

The reaction of cubic gallium arsenide (GaAs) with ammonia yielded gallium nitride (GaN). Powder X-ray diffraction patterns of the GaN products showed that they are a mixture of c- and w-GaN, while their Ga MAS NMR spectra revealed that they have the other phase of GaN besides c- and w-GaN and the high reaction temperature (≥900 °C) induces nitrogen deficiency in GaN. The peaks at 353 and 347 ppm in the ⁷¹Ga MAS NMR spectra were tentatively assigned to c-GaN and an intermediate of w- and c-GaN in the stacking order, respectively. The observed ⁷¹Ga chemical shifts of GaN, GaP, GaAs and GaSb in cubic phase were well correlated with the reciprocal of their band gaps.     

Gallium nitride formed by vapour deposition and by conversion from gallium arsenide

Attempts to prepare single crystal gallium nitride in thin films and bulk form are reported. The thin films were prepared by reacting GaCl₃ and NH₃ and depositing on to single crystal silicon carbide substrates. The bulk gallium nitride was prepared by the conversion of single crystals of gallium arsenide using an intermediate oxide phase. The structural perfection of the gallium nitride material thus formed has been assessed using X-ray diffraction and electron diffraction techniques. Both methods of preparation produced single phase gallium nitride exhibiting a high degree of structural disorder.     

一维氧化镓纳米材料研究进展

随着纳米材料制备技术和性能研究的发展,一维纳米材料日益受到人们的关注.简要介绍了一维氧化镓纳米材料的制备方法及其光致发光机理,并指出了当前研究过程中存在的问题和可能的发展方向.     

镓熔点温坪复现研究

镓熔点是ITS-90国际温标中重要的定义固定点,在温度计量研究中起着重要作用。由于高纯镓从液态转化为固态时,体积膨胀约3.1%,传统玻璃外壳的镓熔点容器在冻制过程中很容易造成损坏。为了解决这一难题,设计了一种具有金属外壳的镓熔点装置,以该装置为对象,开展了2种不同镓熔点复现方法和2种不同复现装置对镓相变温坪影响方面的研究,并与国外同类型装置的性能进行了比较。实验结果表明:不同镓点容器复现的镓熔点温度在0.02 mK范围内一致,高纯镓中的微量杂质是造成差异的主要原因;外液-固界面复现方法比双液-固界面复现方法得到的温坪值低0.09 mK;不同复现装置对镓熔点温坪的影响较小。     

Influence of deposition regime on physical properties of gallium doped zinc oxide films

Zinc oxide films doped by gallium were deposited using RF diode sputtering from a ceramic ZnO + 2% Ga₂O₃ target on Corning glass in argon atmosphere. Samples were supported in three different positions against a substrate holder - horizontal, and at 60 and 80° to the horizontal position. Two series of samples 700-1000 nm in thickness were prepared: one at room temperature (RT) and the second at 200 °C. XRD, optical and electrical experiments indicated that the films are polycrystalline having average crystallite sizes from 30 to 80 nm, integrated transmittances in the range of 400-1000 nm increased from 85 to 90 per cent and optical band-gap values increased from 3 to 3.2 eV with higher deposition temperature. The resistivity of the obliquely sputtered samples positioned at 80° to the substrate holder was one order lower than the horizontally positioned samples. No significant changes were observed in case of optical properties of the films in dependence on the tilt-angle.     

液相共沉淀法制备钆镓石榴石(Gd3Ga5O12,GGG)多晶原料

采用液相共沉淀法制备了钆镓石榴石（GGG）的多晶原料，给出了液相合成GGG多晶粒的工艺步骤及其条件，就组分Gd2O3和Ga2O3的配比，滴定氧化物溶解的混合溶液使其沉淀的PH值，共沉淀后烧结温度以及烧结时间等影响GGG多晶粒合成的重要因素进行了讨论，通过和固相合成GGG多晶粒的条件比较可知，液相合成GGG多晶原料的工艺具有合成的GGG多晶料均匀充分，合成温度低与烧结时间短等优点。     

Characterization of oxidized gallium droplets on silicon surface: An ellipsoidal droplet shape model for angle resolved X-ray photoelectron spectroscopy analysis

Deposition and oxidation of metallic gallium droplets on Si(111) were studied by angle resolved X-ray photoelectron spectroscopy. Two gallium peaks - Ga 3d and Ga 2p - were simultaneously measured in order to get an advantage of different inelastic mean free paths of photoelectrons from these two energy levels differing in binding energy by 1100 eV. Together with the angular dependent data it enhances the precision of the size characterization of Ga droplets and oxide thickness determination. A model for the calculation of theoretical intensities based on an ellipsoidal shape of droplets is presented and a simple procedure for estimation of droplet height and actual surface coverage based on measurement on a single emission angle is suggested.     

溶液中镓的提取与分离研究进展

从钢铁、有色金属、煤化工及磷化工等行业中的含镓物料中回收镓,需面临从含有多种金属离子的溶液中分离镓的问题。综述了含镓溶液中提取和分离镓的研究现状,分析和讨论了溶剂萃取、液膜萃取、萃淋树脂萃取等工艺的关键影响因素,并展望了研究趋势。溶剂萃取、液膜萃取及萃淋树脂萃取工艺皆能有效提取和分离溶液中的镓,其中协同萃取、液膜萃取及萃淋树脂萃取的选择性和萃取效率高,而且流程短、环境友好,应用前景好,是今后研究的发展方向。     

High Spatial Resolution Mapping of Localized Surface Plasmon Resonances in Single Gallium Nanoparticles

Plasmonics has emerged as an attractive field driving the development of optical systems in order to control and exploit light–matter interactions. The increasing interest around plasmonic systems is pushing the research of alternative plasmonic materials, spreading the operability range from IR to UV. Within this context, gallium appears as an ideal candidate, potentially active within a broad spectral range (UV–VIS–IR), whose optical properties are scarcely reported. Importantly, the smart design of active plasmonic materials requires their characterization at high spatial and spectral resolution to access the optical fingerprint of individual nanostructures, attainable by transmission electron microscopy techniques (i.e., by means of electron energy‐loss spectroscopy, EELS). Therefore, the optical response of individual Ga nanoparticles (NPs) by means of EELS measurements is analyzed, in order to spread the understanding of the plasmonic response of Ga NPs. The results show that single Ga NPs may support several plasmon modes, whose nature is extensively discussed.     

A precise measurement of some nonlinear effects and its application to the evaluation of nonlinear elastic constants of quartz and GaPO4

This paper deals with a precise measurement of amplitude frequency and intermodulation effects, and its application to the evaluation of nonlinear elastic constants of quartz and gallium orthophosphate (GaPO/sub 4/). An evaluation is based on the methods used previously concerning determination of the higher-order material constants in the quartz. Using a measurement of the intermodulation products and measurement of drive level dependence of resonant frequency of quartz resonators, we have determined some effective elastic constants of fourth order. The computer-based method of solution of the set of equations gives an access to obtain a number of effective nonlinear stiffnesses of fourth order. The measurements and computer solutions are performed on different Y-cuts resonators, both for quartz and gallium orthophosphate resonators, vibrating in fundamental thickness shear mode. The experimental results are discussed.