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学的科学技术潜力，研究了多孔硅的可见光发光机制，包括单片光子集成的器件物理。主要研究成果总结如下：1.研究成果。发光机理的相关问题：(1)发光多晶硅的电子结构和晶格结构保持了单晶硅衬底的特征，但其禁带宽度变宽。(2)禁带宽度与光致发光峰值能量之间存在一定的相关性。(3)在对光致发光动力学、偏振记忆和光致发光激发过程进行光谱分析的基础上，提出了与纳米晶体相关的光致发光模型。(4)光致发光光谱可以通过后阳极氧化光化学刻蚀实现从红色到蓝色的连续调谐。(5)通过适当控制PS2中硅纳米晶的结构和表面终止，可以提高光致发光效率和稳定性。集成光子器件的基本原理(1)通过对PS二极管电致发光(EL)机理的分析，得到具有简单PS层的二极管的效率为0.05%。(2)基于单片制作技术，证明了PS可用于光腔和三维掩埋波导。(3)利用非线性光学效应，明确了PS用于光学逻辑门的可行性。(4)观察到PS作为受限系统与EL发射相关的一些有用的功能。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.