tailieunhanh - Báo cáo hóa học: " Cu-Doping Effects in CdI2 Nanocrystals: The Role of Cu-Agglomerates"

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: Cu-Doping Effects in CdI2 Nanocrystals: The Role of Cu-Agglomerates | Nanoscale Res Lett 2009 4 187-190 DOI s11671-008-9215-4 NANO PERSPECTIVES Cu-Doping Effects in CdI2 Nanocrystals The Role of Cu-Agglomerates M. Idrish Miah Received 12 September 2008 Accepted 11 November 2008 Published online 22 November 2008 to the authors 2008 Abstract Cu-doping effects in CdI2 nanocrystals are studied experimentally. We use the photostimulated second harmonic generation PSSHG as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1 reduces to that for the undoped CdI2 crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects. Keywords Nanocrystals Defects Surface properties Electron-phonon interaction Introduction Nonlinear spectroscopy and photostimulated second harmonic generation PSSHG are the two important tools to investigate the higher-order nonlinear optical processes in particular in semiconductors 1 . The PSSHG is prevented by symmetry in a centrosymmetric material process. So in order to observe the PSSHG one needs to have a M. I. Miah H Nanoscale Science and Technology Centre Griffith University Nathan Brisbane QLD 4111 Australia e-mail M. I. Miah School of Biomolecular and Physical Sciences Griffith University Nathan Brisbane QLD 4111 Australia M. I. Miah Department of Physics University of Chittagong Chittagong 4331 Bangladesh noncentrosymmetric process. Fortunately there are different ways to enhance the PSSHG. These include 1 the reduction of the size of the crystals to the nanometer scale 2 lowering the crystal temperature and 3 insertion of suitable impurities into the crystal with an appropriate amount 1 . The nanometer-sized crystals take into account the quantum-confined effect quantum confinement dominates the material s electronic