Development and Photonic Integration of Efficient and Stable Silicon-Based LED

为了开发高效稳定的硅基LED，使单片光子集成的技术基础更加坚实，在制作工艺、表面钝化和相关光电表征方面进行了实验研究。主要研究结果及其意义总结如下：1。通过引入后阳极化电化学处理，成功地降低了多孔硅二极管中的泄漏成分电流，并将载流子注入到发光纳米晶硅中变得非常高效。因此，外部量子效率提高到1%以上。此外，可以从具有适当器件配置的二极管获得接近实际水平的0.4%的外部功率效率。这是该领域迄今为止的最高值。阐明了稳定发光二极管工作和调节发光带的几个关键问题。特别重要的结果是，在无氧化物的样品中观察到蓝色辐射。硅纳米晶体新功能的发现从一些电学和光学研究中，已经表明发光纳米晶体硅具有多种有用的功能：发光非易失性存储器，弹道电子发射和热诱导超声发射。纳米晶硅是一种非常有用的多功能材料。面向光子集成研究了纳米晶硅与三维埋地光波导的相容性。实验证明，通过简单的平面加工，可以制造出曲率极小的埋式弯曲波导。折射率变化引起的非线性光学效应也被观察到。

To develop efficient and stable silicon-based LED and make the technological foundation of monolithic photonic integration more solid, experimental studies have been conducted in terms of fabrication technique, surface passivation, and related optoelectronic characterization. The major results and their significances are summarized as follows.1. Drastic improvement in the efficiency of Si-based LEDsBy introducing a post-anodization electrochemical treatment, the leakage component in the porous silicon diode current is successfully reduced, and carrier injection into luminescent nanocrystalline silicon becomes very efficient. As a result, the external quantum efficiency is enhanced to beyond 1%. Also, an external power efficiency of 0.4% close to a practical level can be obtained from a diode with an appropriate device configuration. These are the highest values to date in this field. Some key issues for stabilization of LED operation and for tuning the emission band have also been clarified. Especially important result is that blue emission has been observed with oxide-free samples.2. Findings of novel functions of silicon nanocrystalsFrom some electrical and optical investigations, it has been shown that luminescent nanocrystalline silicon exhibits various useful functions : light-emissive nonvolatile memory, ballistic electron emission, and thermally induced ultrasonic emission. Nanocrystalline silicon is very useful as a multi-functional material.3. Toward photonic integrationThe compatibility of nanocrystalline silicon with three-dimensional buried optical waveguide was examined. It has been demonstrated that a buried bent waveguide with an extremely small curvature can be fabricated by simple palanar processing. Nonlinear optical effects due to refractive index change were also observed.