共查询到18条相似文献,搜索用时 171 毫秒
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纳米量子点结构的自组织生长 总被引:4,自引:2,他引:2
彭英才 《固体电子学研究与进展》2000,20(2):160-168
所谓自组织生长纳米量子点 ,是具有较大晶格失配度的两种材料 ,依靠自身的应变能量 ,并以 Stranki- Krastanov(S- K)生长模式 ,在衬底表面上形成的具有一定形状、尺寸和密度的自然量子点结构。文中主要介绍了量子点自组织生长的基本原理、几种不同类型量子点的自组织生长及其光致发光特性。 相似文献
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所谓半导体量子点的自组织生长,是指具有较大晶格失配度的两种材料,依靠自身的应变能量,并以Stranki-Krastanov(S-K)生长模式,在衬底表面上形成的一定形状、尺寸和密度分布的自然量子点结构。本文主要介绍了纳米量子点的自组织生长,自组织生长最子点的发光特性及其在光电器件中的应用。 相似文献
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采用低压化学气相沉积方法,依靠纯SiH4气体的热分解反应,在SiO2表面上自组织生长了Si纳米量子点.实验研究了SiO2膜的薄层化对Si纳米量子点光致发光特性的影响.结果表明,当SiO2膜厚度减薄至6nm以下时,Si纳米量子点中的光生载流子会量子隧穿超薄SiO2层,并逃逸到单晶Si衬底中去,从而减少了光生载流子通过SiO2/Si纳米量子点界面区域内发光中心的辐射复合效率,致使光致发光强度明显减弱.测试温度的变化对Si纳米量子点光致发光特性的影响,则源自于光生载流子通过SiO2/Si纳米量子点界面区域附近非发光中心的非辐射复合所产生的贡献. 相似文献
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SiO2膜的薄层化对自组织生长Si纳米量子点发光特性的影响 总被引:4,自引:0,他引:4
采用低压化学气相沉积方法,依靠纯SiH4气体的热分解反应,在SiO2表面上自组织生长了Si纳米量子点.实验研究了SiO2膜的薄层化对Si纳米量子点光致发光特性的影响.结果表明,当SiO2膜厚度减薄至6nm以下时,Si纳米量子点中的光生载流子会量子隧穿超薄SiO2层,并逃逸到单晶Si衬底中去,从而减少了光生载流子通过SiO2/Si纳米量子点界面区域内发光中心的辐射复合效率,致使光致发光强度明显减弱.测试温度的变化对Si纳米量子点光致发光特性的影响,则源自于光生载流子通过SiO2/Si纳米量子点界面区域附近非发光中心的非辐射复合所产生的贡献. 相似文献
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Strained epitaxy has been shown to produce pyramidal-shaped semiconductor dot structures by single-step epitaxy. The very high density of these dots (approaching per wafer) and their ever improving uniformity suggest that these features could have important applications in future microelectronics. Understanding the structural and electronic properties of these quantum dots is therefore of great importance. In this paper, we examine some of the physics controlling the performance of devices that could be made from such structures. The self-assembled quantum dots are highly strained and we will examine the strain tensor in these quantum dots using a valence force-field model. In this paper we will address the following issues: (1) What is the general nature of the strain tensor in self assembled quantum dots? (2) What are the electron and hole spectra for InAs-GaAs quantum dots? (a) What are the important intersubband radiative and nonradiative scattering processes in the self assembled quantum dots? In particular, we will discuss how the electron-phonon interactions are modified in the quantum dot structures. Consequences for uncooled intersubband devices such as lasers, detectors, and quantum transistors will be briefly discussed 相似文献
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《Microelectronics Journal》1999,30(4-5):341-345
We present investigations of the structural and optical properties of in-situ etched, self assembled InAs islands using AsBr3 within a molecular beam epitaxy system. This procedure allows reshaping and downsizing of quantum dots with atomic layer precision. The critical thickness of a second InAs layer on top of a thin GaAs layer covering a first InAs dot layer was investigated by RHEED using the 2D–3D transition due to the Stranski–Krastanov growth mode. In-situ etching of the GaAs spacer layer results in an array of small dips on the surface due to enhanced etching at locally strained areas. The dips influence the nucleation of the second dot layer. 相似文献
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Semiconductors - In this work, Experimental study of the influence of internal electric field and the temperature on the photoluminescence of InAs self assembled quantum dots inserted in... 相似文献
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Rémi Beaulac Paul I. Archer Stefan T. Ochsenbein Daniel R. Gamelin 《Advanced functional materials》2008,18(24):3873-3891
Recent advances in the chemistry of colloidal semiconductor nanocrystal doping have led to new materials showing fascinating physical properties of potential technological importance. This article provides an overview of efforts to dope one of the most widely studied colloidal semiconductor nanocrystal systems, CdSe quantum dots, with one of the most widely studied transition‐metal dopant ions, Mn2+, and describes the major new physical properties that have emerged following successful synthesis of this material. These properties include spin‐polarizable excitonic photoluminescence, magnetic circular dichroism, exciton storage, and excitonic magnetic polaron formation. A brief survey of parallel advances in the characterization of analogous self‐assembled Mn2+‐doped quantum dots grown by molecular beam epitaxy is also presented, and the physical properties of the colloidal quantum dots are shown to compare favorably with those of the self‐assembled quantum dots. The rich variety of physical properties displayed by colloidal Mn2+‐doped CdSe quantum dots highlights the attractiveness of this material for future fundamental and applied research. 相似文献
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Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
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《Microelectronics Journal》1999,30(4-5):419-425
Optical and morphological properties of self assembled In(Ga)As/GaAs quantum dot systems, grown on high index (N11) substrates, for a wide range of orientations, coverages and compositions, are presented and reviewed. The use of high Miller index substrate orientations permits to intervene on major quantum dots properties such as shape, size distribution, transition energy and emission polarisation, thus opening a wide range of device design opportunities. 相似文献
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Chih‐Wei Hsu Abhijit Ganguly Chi‐Hui Liang Yu‐Ting Hung Chien‐Ting Wu Geng‐Ming Hsu Yang‐Fang Chen Chia‐Chun Chen Kuei‐Hsien Chen Li‐Chyong Chen 《Advanced functional materials》2008,18(6):938-942
We report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self‐assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH3 via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In‐rich or Ga‐rich ternary NWs have been produced. X‐ray diffraction, Raman studies and transmission electron microscopy reveal a phase‐separated microstructure wherein the isovalent heteroatoms are self‐aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In‐rich and Ga‐rich NWs. Temperature‐dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga‐rich NWs to their embedded SAQDs. A multi‐level band schema is proposed for the case of In‐rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position. 相似文献