Photonics Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
Nano Lett. 2016 Feb 10;16(2):1056-63. doi: 10.1021/acs.nanolett.5b04190. Epub 2016 Jan 14.
High-quality nitride materials grown on scalable and low-cost metallic substrates are considerably attractive for high-power light-emitters. We demonstrate here, for the first time, the high-power red (705 nm) InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) self-assembled directly on metal-substrates. The LEDs exhibited a low turn-on voltage of ∼2 V without efficiency droop up to injection current of 500 mA (1.6 kA/cm(2)) at ∼5 V. This is achieved through the direct growth and optimization of high-quality nanowires on titanium (Ti) coated bulk polycrystalline-molybdenum (Mo) substrates. We performed extensive studies on the growth mechanisms, obtained high-crystal-quality nanowires, and confirmed the epitaxial relationship between the cubic titanium nitride (TiN) transition layer and the hexagonal nanowires. The growth of nanowires on all-metal stack of TiN/Ti/Mo enables simultaneous implementation of n-metal contact, reflector, and heat sink, which greatly simplifies the fabrication process of high-power light-emitters. Our work ushers in a practical platform for high-power nanowires light-emitters, providing versatile solutions for multiple cross-disciplinary applications that are greatly enhanced by leveraging on the chemical stability of nitride materials, large specific surface of nanowires, chemical lift-off ready layer structures, and reusable Mo substrates.
在可扩展且低成本的金属衬底上生长高质量的氮化物材料对于高功率光发射器具有很大的吸引力。我们首次在这里展示了在金属衬底上自组装的直接生长在金属衬底上的大功率红色（705nm）InGaN/GaN 量子盘（Qdisk）-纳米线发光二极管（LED）。这些 LED 的开启电压低至约 2V，在约 5V 时，在 500mA（1.6kA/cm(2)）的注入电流下没有效率下降。这是通过在涂钛（Ti）的多晶钼（Mo）衬底上直接生长和优化高质量纳米线来实现的。我们对生长机制进行了广泛的研究，获得了高晶体质量的纳米线，并确认了立方氮化钛（TiN）过渡层与六方纳米线之间的外延关系。TiN/Ti/Mo 全金属叠层上纳米线的生长可以同时实现 n 型金属接触、反射器和散热器，这大大简化了高功率光发射器的制造工艺。我们的工作为高功率纳米线发光器提供了一个实用的平台，通过利用氮化物材料的化学稳定性、纳米线的大比表面积、可进行化学剥离的准备层结构以及可重复使用的 Mo 衬底，为多个跨学科应用提供了通用的解决方案，这些应用得到了极大的增强。
