| Photonics, a blending of optics and electronics, has emerged as one of the world's most rapidly developing fields. Along with microelectronics, they constitute the core technologies of the information industry, and their advances are complementing each other in the tasks of the acquisition, transmission, storage, and processing of increasing amounts of information. Microelectronic device integration has progressed to the point that complete “systems-on-the-chip” have been realized. Photonic materials need to be integrated with standard electronic circuits for the implementation of the next generation optoelectronic “super-chip” where both electrons and photons participate in the transmission and processing of information.; Silicon is the cornerstone material in conventional VLSI systems. However, having a relatively small and indirect fundamental energy band-gap, silicon is an inefficient lightemitter. On the other hand, direct integration of III-V photonic materials on a silicon chip is still very problematic. Squeezing light out of silicon itself appears to be an attractive alternative. Light emission from silicon is an important fundamental issue with enormous technological implications. In this work we explore several strategies towards developing silicon based optoelectronic devices.; Porous silicon, a material produced by electrochemically etching silicon in aqueous hydrofluoric acid solutions, generated great interest in the early 1990s when it was shown to exhibit relatively bright, room temperature, visible photoluminescence. However, having a poor surface morphology, the material is fragile and chemically unstable leading to degradation of light emission and preventing integration with silicon processing technology.; With the development of the epitaxially grown crystalline-Si/O superlattice, we attempt to overcome the morphological problems of porous silicon, retaining its light emission characteristics. Our multilayer c-Si/O device consists of thin silicon layers sandwiched between monolayers of oxygen. The key for its fabrication is that epitaxial growth of silicon may be continued beyond the interruption with exposure to oxygen. Prepared by an Ultra High Vacuum (UHV), Molecular Beam Epitaxial (MBE) technique, the multilayer device is extremely stable and robust, and can be readily integrated with conventional silicon VLSI processing. In addition, it exhibits bright, room temperature, visible photoluminescent and electroluminescent emission, at least as strong as that of porous silicon. With its efficient light emission, robustness and stability, the c-Si/O superlattice may hold the promise of a truly integrated silicon-based optoelectronic device. |
