ZnCl2掺杂n型ZnSe的分子束外延生长

利用分子束外延(MBE)技术,以5N的ZnCl2作为掺杂源,在半绝缘GaAs (001)衬底上异质外延生长ZnSe:Cl单晶薄膜.研究发现,掺入ZnCl2后,ZnSe外延层的结晶质量和表面形貌与本征ZnSe外延层相比变差,双晶X射线摇摆曲线(DCXRC)的ZnSe (004)衍射峰半峰宽(FWHM)从432 arcsec增大到529 arcsec,表面均方根粗糙度(RMS)从3.00 nm增大到3.70nm.当ZnCl2掺杂源炉的温度为170℃时,ZnSe样品的载流子浓度达到1.238×1019 cm-3,可以满足结型器件制作和隧道结材料设计的要求.     

MBE生长Zn1—xCdxSe／ZnSe超晶格的SIMS和AES谱

本简要叙述了运用ＭＢＥ技术成功生长出Ｚｎ１－ｘＣｄｘＳｅ／ＺｎＳｅ超晶格的一些工艺和渗数，并对不同的样品进行了ＳＩＭＳ和ＡＥＳ的测试，首次测得了这种材料的元素分布，结果显示ＺｎＣｄＳｅ／ＺｎＳｅ超晶格有良好的纵向元素分布。     

Growth and photoluminescence study of ZnSe quantum dots

We report detailed photoluminescence (PL) studies of ZnSe quantum dots grown by controlling the flow duration of the precursors in a metal-organic chemical vapor deposition system. The growth time of the quantum dots determines the amount of blue shift observed in the PL measurements. Blue shift as large as 320 meV was observed, and the emission was found to persist up to room temperature. It is found that changing the flow rate and the total number of quantum dot layers also affect the peak PL energy. The temperature dependence of the peak PL energy follows the Varshni relation. From analyzing the temperature-dependent integrated intensity of the photoluminescence spectra, it is found that the activation energy for the quenching of photoluminescence increases with decreasing quantum dot size, and is identified as the binding energy of the exciton in ZnSe quantum dot.     

ZnSe单晶薄膜生长控制和掺杂控制

为研制ZnSe基蓝绿色半导体激光器,必须能够对组成激光器的各单元材料实现精确控制生长,包括材料的晶体质量、掺杂浓度和生长速度等。ZnSe是制备蓝绿激光器的基础材料,本文报道利用MBE技术对ZnSe材料进行生长控制和掺杂控制的初步研究结果。     

低温下应变外延层的单层生长

用接触式原子力显微镜来观察 4 6 0℃低温下生长的 In0 .35Ga0 .6 5As/ Ga As外延层形貌 .实验发现 ,这种 4 6 0℃低温生长材料的失配外延层既不是层状的 Fvd M生长模式也不是岛状的 SK自组织生长模式 ,而是由原子单层构成的梯田状大岛 .原子力显微镜测试表明台阶的厚度为 0 .2 8nm,约为一个原子单层 ,这种介于层状和岛状生长之间的模式有助于了解失配异质外延的生长过程     

低温下应变外延层的单层生长

用接触式原子力显微镜来观察460℃低温下生长的In0.35Ga0.65As/GaAs外延层形貌.实验发现,这种460℃低温生长材料的失配外延层既不是层状的FvdM生长模式也不是岛状的SK自组织生长模式,而是由原子单层构成的梯田状大岛.原子力显微镜测试表明台阶的厚度为0.28nm,约为一个原子单层,这种介于层状和岛状生长之间的模式有助于了解失配异质外延的生长过程.     

Growth and characterization of digital alloy quantum wells of CdSe/ZnSe

We report a study of digital alloy quantum wells of CdSe/ZnSe grown by migration enhanced epitaxy. The quantum well regions consist of various numbers of periods of one monolayer of CdSe and three monolayers of ZnSe, and the barriers are ZnSe. It will be shown that the optical properties of such quantum wells are greatly affected by the structural quality of the digital alloy. Both structural and optical properties will be discussed. Such digital alloy quantum wells are shown to have excellent room temperature optical characteristics.     

在ZnO/Si衬底上ZnCdSe/ZnSe多量子阱的生长与光学特性

在经NH3等离子体氮化的Si(100)衬底上。用等离子体增强化学气相淀积(PECVD)的方法生长了ZnO缓冲层，经X射线衍射(XRD)测量，得到了单一取向的ZnO(0002)膜。在此ZnO缓冲层上利用低压金属有机化学气相淀积(LP-MOCVD)方法生长了较高质量的ZnCdSe／ZnSe量子阱。通过不同阱宽的ZnCdSe／ZnSe量子阱生长和测量，得到了多级共振拉曼峰。从发光谱中可见，在1520nm附近有很强的发光，而在未覆盖ZnO的Si衬底上直接生长的ZnCdSe／ZnSe量子阱结构，其光致发光(PL)谱未见发光。可见，在氮化的Si衬底上覆盖ZnO膜生长的ZnCdSe/ZnSe量子阱质量较好。是一种在Si衬底上生长Ⅱ-Ⅵ族化合物半导体材料的有效方法。     

Optical Properties and Growth Aspects of Silver Nanoprisms Produced by a Highly Reproducible and Rapid Synthesis at Room Temperature

A rapid and readily reproducible seed‐based method for the production of high quality silver nanoprisms in high yield is presented. The edge‐length and the position of the main plasmon resonance of the nanoprisms can be readily controlled through adjustment of reaction conditions. From UV‐vis spectra of solutions of the nanoprisms, the inhomogeneously broadened line width of the in‐plane dipole plasmon resonance is measured and trends in the extent of plasmon damping as a function of plasmon resonance energy and nanoprism size have been elucidated. In addition, an in‐depth analysis of the lamellar defect structure of silver nanoprisms is provided that confirms that the defects can lead to a transformation of the crystal structure in the vicinity of the defects. These defects can combine give rise to lamellar regions, thicker than 1 nm, that extend across the crystal, where the silver atoms are arranged in a continuous hexagonal‐close‐packed (hcp) structure. This hcp structure has a periodicity of 2.50 Å, thus explaining the 2.50 Å lattice fringes that are commonly observed in 〈111〉 oriented flat‐lying nanoprisms. A new understanding of the mechanisms behind anisotropic growth in silver nanoprisms is presented.     

Direct Growth of Nanopatterned Graphene on Sapphire and Its Application in Light Emitting Diodes

Direct growth of graphene films on functional substrates is immensely beneficial for the large‐scale applications of graphene by avoiding the transfer‐induced issues. Notably, the selective growth of patterned graphene will further boost the development of graphene‐based devices. Here, the direct growth of patterned graphene on the c‐plane of nanopatterned sapphire substrate (NPSS) is realized and the superiority of the patterned graphene for high‐performance ultraviolet light‐emitting diodes (UV‐LED) is demonstrated. As confirmed by density functional theory calculations and analog simulations, compared to the concave r‐plane the flat c‐plane of NPSS is characterized by a lower active barrier for methane decomposition and carbon species diffusion, as well as a greater supply of carbon precursor for graphene growth. The synthesized patterned graphene on the c‐plane of NPSS is verified to be monolayer and high quality. The patterned graphene enables the selective and well‐aligned nucleation of aluminium nitride (AlN) to promote rapid epitaxial lateral overgrowth of single‐crystal AlN films with low dislocation density. Consequently, the fabricated UV‐LED demonstrates high luminescence intensity and stability. The method is suitable for obtaining various patterned graphene by substrate design, which will allow for greater progress in the cutting‐edge applications of graphene.     

高温超导YBa2Cu3O7薄膜的颗粒,杂相生长机制研究

ＹＢａ２Ｃｕ３Ｏ７（ＹＢＣＯ）高温超导薄膜是重要的超导电子器件应用的材料，它们的质量对器件的运行性能至关重要。薄膜表面的颗粒使表面微波性能变坏，但有些生长在ＹＢＣＯ薄膜基体内部的小颗粒，会使薄膜的临界电流密度升高。     

碲锌镉晶体生长炉自主设计与控温性能实验

针对直径4英寸碲锌镉单晶材料生长的需求,在研究国外碲锌镉晶体材料生长取得的成果基础上,自主设计了一种基于移动炉体技术的碲锌镉晶体生长炉.炉体由4种规格的六段温控加热单元组成,采用工控机控制伺服电机来驱动滚珠丝杆直线导轨实现炉体升降,炉体内腔设置有刚玉陶瓷管及高温金属热管组成的加热炉管,通过高精度铂铑铂热电偶、欧陆、变压...