水之魂 (The Soul of Water)分享 http://blog.sciencenet.cn/u/ecqsun 上善若水

博文

局域键平均3: Dielectrics & optoelectrinics of nanosolid Si

已有 2403 次阅读 2011-12-31 15:28 |个人分类:控键工程|系统分类:论文交流|关键词:键

Dielectric and optoelectronic engineering of silicon

http://www3.ntu.edu.sg/home/ecqsun/pms-Si.docx

Nanostructured or porous silicon with and without surface passivation forms a kind of amazing materials that has found wide applications in upcoming technologies such as catalysis, bio- and gas- sensors, biofuel cells, drug delivery and phototherapy of cancer cells with highly biodegradability, photon emission and detection, solar energy harvesting, etc. However, the underlying mechanism for the unusual performance of the pure and passivated nano-Si remains yet its infancy and inconsistency. This work is devoted both experimentally and theoretically to the dielectric, electronic, phononic, and photonic performance of Si upon size reduction and surface passivation. Focus will be given mainly on the band gap expansion, the blue shift in photoluminescence and photoabsorption, the electron-phonon interaction, the 2p energy level and the Raman frequency shift, and the dielectric suppression and relaxation as well as their correlations. We found that O and F passivation further enhances the size effect on the observations alteration and that metallization by ultrathin Cu, Al, and Ti coatings also modulates the properties to different extents. Consistency between theory [Prog Mater Sci 2003;48:521; ibid 2009;54:179] expectations and experimental observations clarifies that the unusual dielectric, optoelectronic, and vibronic behavior of the passivated and the pure nano-Si is related directly to the bond nature alteration and the broken-bond-induced local bond contraction and the associated quantum entrapment in the surface of skin depth. Most strikingly, incorporation of the theories to the measurements has enabled determination of the 2p energy level of an isolated Si atom and the vibration frequency of a Si–Si dimer as well as their shift upon bulk and nanosolid formation by matching predictions to the measurements using Raman and XPS, and the activation energy of conductivity of the nano-Si, which are beyond the scope of currently available approaches. Further exploitation on the correlation between the functionality and the developed knowledge would be even more challenging, fascinating and promising for devising advanced functional Si at will.



http://blog.sciencenet.cn/blog-73032-524079.html

上一篇:断键与非健13: ZnO meso-mechano-thermo physical chemistry
下一篇:石墨烯之魂11: 石墨表层和点缺陷选区XPS (ZPS)

4 姜如 秦伟 郭念贵 刘俊明

该博文允许注册用户评论 请点击登录 评论 (0 个评论)

数据加载中...
扫一扫,分享此博文

Archiver|手机版|科学网 ( 京ICP备14006957 )

GMT+8, 2018-11-19 00:43

Powered by ScienceNet.cn

Copyright © 2007- 中国科学报社

返回顶部