tailieunhanh - Báo cáo hóa học: " First-Principles Study of the Band Gap Structure of OxygenPassivated Silicon Nanonets"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: First-Principles Study of the Band Gap Structure of OxygenPassivated Silicon Nanonets | Nanoscale Res Lett 2009 4 409-413 DOI S11671-009-9259-0 NANO EXPRESS First-Principles Study of the Band Gap Structure of Oxygen-Passivated Silicon Nanonets Linhan Lin DeXing Li Jiayou Feng Received 2 November 2008 Accepted 19 January 2009 Published online 6 February 2009 to the authors 2009 Abstract A net-like nanostructure of silicon named silicon nanonet was designed and oxygen atoms were used to passivate the dangling bonds. First-principles calculation based on density functional theory with the generalized gradient approximation GGA were carried out to investigate the energy band gap structure of this special structure. The calculation results show that the indirect-direct band gap transition occurs when the nanonets are properly designed. This band gap transition is dominated by the passivation bonds porosities as well as pore array distributions. It is also proved that Si-O-Si is an effective passivation bond which can change the band gap structure of the nanonets. These results provide another way to achieve a practical silicon-based light source. Keywords Silicon nanonets Oxygen-passivated First-principles calculation Direct band gap Porosity Pore array distribution Introduction Being the basic material of modern integrated circuit technology for decades silicon is one of the most important semiconductor materials. Due to its indirect band gap structure the applications of silicon in optoelectronics are still limited. Nowadays semiconductors with nanoscale structures are of great interest. It is believed that silicon L. Lin D. Li J. Feng H Department of Materials Science and Engineering Key Lab of Advanced Materials Tsinghua University Beijing 100084 China e-mail fengjy@ will develop a direct band gap in nanoscale structures. A number of attempts such as porous silicon 1-3 silicon nanocrystals 4 5 and silicon nanowires 6 7 have been carried out to eliminate the obstacle. Other attempts such as Si SiO2 superlattices structure 8 9