(110)取向的调制掺杂GaAs-AIGaAs单异质结的光致荧光谱

测量了含碳量高低不同的(110)取向的调制掺杂GaAs-Al_0.3Ga_0.7As单异质结在4.2K下的光致荧光谱。在含碳量高的样品中,出现了强的沟道二维电子到受主的复合荧光峰;而在含碳量很低的样品的光致荧光中则只出现体GaAs的荧光峰。     

Electroluminescence of an n-ZnO/p-GaN Heterojunction under Forward and Reverse Biases

Electroluminescent characteristics of n-ZnO/p-GaN heterojunctions under forward and reverse biases are studied. Emissions at 389nm and 57Ohm are observed under forward bias. An unusual emission at 390ram appears under reverse bias, and is attributed to the recombination in the p-GaN side of the heterojunction. The yellow emission peaked at 57Ohm is suppressed under reverse bias. The light intensity exponentially depends on the reverse current. The emission under reverse bias is correlated to tunnelling carrier transport in the heterostructure. Our results also support that the well-known yellow band of GaN comes from the transitions between some near-conduction-band-edge states and deep localized acceptor states.     

Growth of Highly Conductive n-Type Al0.7Ga0.3N Film by Using AlN Buffer with Periodical Variation of Ⅴ/Ⅲ Ratio

High quality and highly conductive n-type Al0.7Ga0.3N films are obtained by using AlN multi-step layers （MSL） with periodical variation of Ⅴ/Ⅲ ratios by low-pressure metalorganic chemical vapour deposition （LP-MOCVD）. The full-width at half-maximum （FWHM） of （0002） and （1015） rocking curves of the Si-doped Al0.7Ga0.3N layer are 519 and 625 arcsec, respectively, Room temperature （RT） Hall measurement shows a free electron concentration of 2.9 × 10^19 cm^-3, and mobility of 17.8cm^2V^-1s^-1, corresponding to a resistivity of 0.0121 Ω cm. High conductivity of the Si-doped AlGaN film with such high Al mole fraction is mainly contributed by a remarkable reduction of threading dislocations （TDs） in AlGaN layer. The TD reducing mechanism in AlN MSL growth with periodical variation of Ⅴ/Ⅲ ratio is discussed in detail.     

256×1甚长波多量子阱红外焦平面线列研制

通过材料设计与制备,甚长波GaAs／AlGaAs多量子阱红外探测器的峰值响应波长14．6μm,响应带宽大于2．2μm．256×1焦平面线列采用垂直入射二维光栅耦合工作模式,45K温度下,单元响应率4．28×10^-2A／W、单元黑体探测率Db＊=5．14×10^9cm．Hz^1.2/W、单元黑体单色探测率Dλ＊=4．24×10^10cm．Hz^1/2/W．通过铟柱与互补式金属一氧化物一半导体读出电路互连得到的甚长波量子阱红外探测器FPA（focal planearray）在积分时间100μs时,有效像元率Nef=99．22％、平均响应率R=3．485×10^6V/W、响应率的不均匀性UR=5．83％、平均黑体探测率典型值Db^＊=2．181×10^8cm．Hz^1/2/w、平均单色探测率Dλ^＊=8．288×10^9cm．Hz^1/2/W．器件已适合进行室温目标的热像图．     

分子束外延材料从基础研究到产业化

文章计概述了分子束外延技术和材料从实验室走向产业化的成功之路,为读者提供了一个了解高技术发展的全过程：由物理学家从理论上提出人工超晶格量子阱材料;再由器件物理学家制备出若干具有重要应用价值的器件与电路,如微波毫米波高电子迁移率晶体管及电路、量子阱激光器,从而促进了分子束外延技术的发展与完善。移动通信、移动互联肉、地面宽带无结通信、汽车防碰撞雷达、高效太阳能电池等对分子束外延材料的需求为其产业化带来     

GaAs/AlxGa1-xAs量子阱能级结构设计与光谱分析

通过理论计算对用于量子阱红外探测器的GaAs/AlxGa1-xAs量子阱能级结构进行模拟设计,将不同生长结构的量子阱材料的光响应谱和光致荧光谱(PL)与计算结果进行比较.说明量子阱生长结构与量子阱能级结构的关系.欲使量子阱红外探测器的响应峰值在8μm附近,则需量子阱结构中阱宽为47nm,垒中Al含量为029.理论计算与测试结果符合得较好. 关键词：     

一种简单高效的制备硅纳米孔阵结构的方法

本文介绍了一种简单高效的制备硅纳米孔阵结构的方法. 利用激光干涉光刻技术, 结合干法和湿法刻蚀工艺, 直接将光刻胶点阵刻蚀为硅纳米孔阵结构, 省去了图形反转工艺中的金属蒸镀和光刻胶剥离等必要步骤, 在2英寸的硅 (001) 衬底上制备了高度有序的二维纳米孔阵结构. 利用干法刻蚀产生的氟碳有机聚合物作为湿法刻蚀的掩膜, 以及在干法刻蚀时对样品进行轻微的过刻蚀, 使SiO₂点阵图形下形成一层很薄的硅台面, 是本方法的两个关键工艺步骤. 扫描电子显微镜图片结果表明制备的孔阵图形大小均匀, 尺寸可控, 孔阵周期为450 nm, 方孔大小为200–280 nm. 关键词： 激光干涉光刻 纳米阵列 刻蚀 氟碳有机聚合物     

Growth of a-Plane GaN Films on r-Plane Sapphire Substrates by Metalorganic Chemical Vapour Deposition

Nonpolar a-plane CaN films were grown on r-plane sapphire substrates by metalorganic chemical vapour deposition (MOCVD) under various conditions. The surface morphologies of epitaxial films are studied by atomic force microscopy. The pit density and size both decrease with the increasing growth temperature, decreasing growth pressure or V/Ⅲ ratio, while the roughness of the surface increases. Formation mechanisms of the pits in the films are discussed.     

高能电子衍射研究H钝化偏角Si衬底上Si,GexSi1-x的分子束外延生长模式

用高能电子衍射(RHEED)研究H钝化偏角Si衬底上Si,Ge_xSi_1-x材料的分子束外延(MBE)生长模式,发现经低温处理的H钝化Si衬底上要经过10nm左右的Si生长才能获得比较平整的表面.Si,Ge_xSi_1-x外延时的稳定表面均以双原子台阶为主,双原子台阶与单原子台阶并存的结构.Si双原子台阶上的Si二聚体列(dimerrow)取向垂直于台阶边缘,而Ge_xSi_1-x双原 关键词：     

NORMAL-INCIDENCE QUANTUM WELL INFRARED PHOTODETECTOR WITHOUT GRATING COUPLER

The n-type GaAs/Al_xGa_1-xAs multiple quantum well infrared photodetectors have been demonstrated without any grating couplers. We have achieved a responsivity R_v of 1.7×10⁵V/W and a detectivity D_λ^* of 4.0×10¹⁰ cm (Hz)^1/2/W for a wavelength of 8.4 μm at a temperature T = 77 K in normal incidence.