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: Thermally Induced Nano-Structural and Optical Changes of nc-Si:H Deposited by Hot-Wire CVD | Nanoscale Res Lett 2009 4 307-312 DOI S11671-008-9243-0 NANO EXPRESS Thermally Induced Nano-Structural and Optical Changes of nc-Si H Deposited by Hot-Wire CVD C. J. Arendse G. F. Malgas T. F. G. Muller D. Knoesen C. J. Oliphant D. E. Motaung S. Halindintwali B. W. Mwakikunga Received 28 October 2008 Accepted 30 December 2008 Published online 21 January 2009 to the authors 2009 Abstract We report on the thermally induced changes of the nano-structural and optical properties of hydrogenated nanocrystalline silicon in the temperature range 200700 C. The as-deposited sample has a high crystalline volume fraction of 53 with an average crystallite size of nm where 66 of the total hydrogen is bonded as Si-H monohydrides on the nano-crystallite surface. A growth in the native crystallite size and crystalline volume fraction occurs at annealing temperatures 400 C where hydrogen is initially removed from the crystallite grain boundaries followed by its removal from the amorphous network. The nucleation of smaller nano-crystallites at higher temperatures accounts for the enhanced porous structure and the increase in the optical band gap and average gap. C. J. Arendse G. F. Malgas C. J. Oliphant D. E. Motaung B. W. Mwakikunga CSIR National Centre for Nano-Structured Materials . Box 395 Pretoria 0001 South Africa e-mail CArendse01@ G. F. Malgas e-mail GMalgas@ C. J. Arendse T. F. G. Muller D. Knoesen C. J. Oliphant D. E. Motaung S. Halindintwali Department of Physics University of the Western Cape Private Bag X17 Bellville 7535 South Africa B. W. Mwakikunga School of Physics University of the Witwatersrand Private Bag 3 . Wits Johannesburg 2050 South Africa B. W. Mwakikunga Department of Physics University of Malawi The Polytechnic Private Bag 303 Blantyre Malawi Keywords Hot-wire CVD Quantum size effects Nano-crystallite Optical band gap Introduction Hydrogenated nanocrystalline silicon nc-Si H has been the subject of intense scientific .
