High-speed nanowire LED in the blue/green spectral range

蓝/绿光谱范围内的高速纳米线 LED

• 批准号: 387904162
• 负责人: Professor Dr. Gerd Bacher
• 金额: --
• 依托单位: Lehrstuhl für Bauelemente der Höchstfrequenzelektronik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387904162?language=en
• 关键词: speed; nanowire; LED; blue; green

High-speed optical data communication via free space or polymer optical fibre requires fast, safe, and low-cost light sources. At present red light sources (650 nm) are routinely used for polymer fibre data transport although a blue/green light source (< 520 nm) would provide a much lower intensity loss during fibre transmission. GaN/GaInN light emitting diodes emitting in the blue/green spectral regime are commercially available. However, the layer stacks of these diodes are grown in the c-direction of the wurtzite lattice causing a pronounced spatial separation of electrons and holes in the active InGaN quantum well due to spontaneous polarization. This separation results in long radiative lifetimes up to some 10 ns and fundamentally limits the achievable data rate using GaN/GaInN light emitting diodes.The key idea of this project is to completely eliminate the spontaneous polarization in order to increase the radiative recombination rate and to push the achievable modulation frequency up to above 2,000 MHz. Our approach is a core-shell nanowire arrangement consisting of a n-GaN core followed by a polarization-free m-plane shell composed of an active InGaN quantum well and a p-GaN contact layer. The device is realized by an array of core-shell GaN/InGaN nanowires grown on a conductive n-type silicon substrate. The free-space between the wires will be filled-up and a transparent top layer will serve as the anode of the device. A combination of self-catalytic and selective-area epitaxy shall be developed in order to provide the mandatory homogeneity of the nanowires within an array of nanowires and across the wafer.A distinct challenge is the elucidation of limiting recombination and relaxation mechanisms providing key information for the design and technology of a high-speed light source for optical data transmission. Time-resolved (< 100 ps) optical and optoelectronic measurements will be performed on the nanowire light sources with high spatial resolution (< 0.3 µm) in order to localize device limitations with respect to e.g. speed, intensity, and spectral line width of emission. The results will be directly incorporated into the design and technology of the devices. In parallel, the electrical high-frequency performance of the devices will be evaluated and optimized by scattering parameter measurements and equivalent circuit analysis. The fundamental goal of this project is the scientific development of a light source at frequencies above 2,000 MHz for free-space and polymer optical fibre data transmission.

通过自由空间或聚合物光纤的高速光数据通信需要快速、安全和低成本的光源。目前，红光源（650 nm）通常用于聚合物纤维数据传输，尽管蓝/绿色光源（< 520 nm）在纤维传输期间将提供低得多的强度损失。在蓝色/绿色光谱范围内发射的GaN/GaInN发光二极管是市售的。然而，这些二极管的层堆叠在纤锌矿晶格的c方向上生长，由于自发极化，导致有源InGaN量子阱中的电子和空穴的显著空间分离。这种分离导致了长达10 ns的辐射寿命，并从根本上限制了使用GaN/GaInN发光二极管可实现的数据速率。该项目的关键思想是完全消除自发极化，以提高辐射复合率，并将可实现的调制频率推高至2,000 MHz以上。我们的方法是一个核-壳纳米线的安排组成的n-GaN核心，然后由一个无偏振的m-平面壳组成的有源InGaN量子阱和p-GaN接触层。该器件是通过在导电的n型硅衬底上生长的核-壳GaN/InGaN纳米线阵列来实现的。导线之间的自由空间将被填满，透明的顶层将用作器件的阳极。自催化和选择性区域外延的组合应被开发，以提供强制性的均匀性的纳米线阵列内的纳米线和整个wafer.A独特的挑战是限制复合和弛豫机制的阐明提供关键信息的设计和技术的高速光源的光学数据传输。将对具有高空间分辨率（< 0.3 µm）的纳米线光源进行时间分辨（< 100 ps）的光学和光电测量，以定位关于例如发射的速度、强度和谱线宽度的器件限制。结果将直接纳入设备的设计和技术。同时，将通过散射参数测量和等效电路分析来评估和优化器件的电气高频性能。该项目的基本目标是科学开发频率在2 000兆赫以上的光源，用于自由空间和聚合物光纤数据传输。