Study of Visible Luminescence Mechanism in Porous Silicon and Its Devvelopment into Silicon-Based Optoelectronic Integration

为了提高硅基光电子技术的科技潜力，研究了多孔硅（PS）的可见发光机制，包括单片光子集成的器件物理。主要研究结果总结如下：发光机理相关问题(1)发光PS存在带隙加宽，但其电子和晶格结构保持单晶硅衬底的特征。(2)带隙与PL峰值能量之间存在一定的相关性。(3)在光谱学分析发光动力学、极化记忆和发光激发过程的基础上，提出了纳米晶体相关的发光模型。(4)单纯通过后阳极化光化学蚀刻，无需热氧化等进一步处理，即可实现光谱从红色到蓝色的连续调谐。(5)通过适当控制ps中硅纳米晶体的结构和表面末端，可以提高PL效率和稳定性。集成光子器件的基本原理(1)通过分析PS二极管的电致发光机理，采用简单PS层的二极管的电致发光效率可达0.05%。(2)基于单片制造技术，论证了PS在光腔和三维埋地波导中的适用性。(3)利用非线性光学效应，明确了PS光逻辑门的可用性。(4)观测到PS作为受限系统的一些有用函数与EL发射有关。尤其重要的是双稳态记忆效应和弹道电子发射。

To enhance the scientific and teachnological potential of silicon-based optoelectronics, the visible luminescence mechanism of porous silicon(PS)has been studied, including the device physics for monolithic photonic integrataion. Major results are summarized as fofllows.1. Related issues to luminescence mechanism(1) Bandgap widening occurs in luminescent PS,while its electronic and lattice structures maintain characteristic features of single-crystal silicon substrates.(2) Definite correlation exists between bandgap and PL peak energy.(3) Nanocrystal-related PL model is presented on a basis of spectroscopic analyzes of PL dynamics, polarization memory, and PL excitation process.(4) PL spestra can be continuously tuned from red to blue simply by post-anodization photochemical etching without any further treatments like thermal oxidation.(5) PL efficiency and stability can be improved by appropriate control of structure and surface termination of silicon nanocrystals in PS.2. Fundamentals of integrated photonic devices(1) By analyzes of electroluminescence (EL) mechanism in PS diodes, efficiency of 0.05% was obtained from diodes with a simple PS layr.(2) Applicability of PS to optical cavity and three-dimensionally buried waveguide was demonstrated based on monolithic fabricataion technology.(3) Availabilty of PS for optical logic gate was made clear by making use of non-linear optical effects.(4) Some useful functions of PS as a confined system were observed in relation to the EL emission. Especially of importances are bistable memory effects and ballistic electron emission.