tailieunhanh - Báo cáo hóa học: " Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared "

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: Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared | Nanoscale Res Lett 2008 3 534-539 DOI S11671-008-9175-8 NANO IDEAS Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared Photodetectors . Yang . Chen W. Lu Y. Fu Received 24 July 2008 Accepted 11 September 2008 Published online 21 October 2008 to the authors 2008 Abstract We present a systemic theoretical study of the electronic properties of the quantum dots inserted in quantum dot infrared photodetectors QDIPs . The strain distribution of three different shaped quantum dots QDs with a same ratio of the base to the vertical aspect is calculated by using the short-range valence-force-field VFF approach. The calculated results show that the hydrostatic strain SH varies little with change of the shape while the biaxial strain SB changes a lot for different shapes of QDs. The recursion method is used to calculate the energy levels of the bound states in QDs. Compared with the strain the shape plays a key role in the difference of electronic bound energy levels. The numerical results show that the deference of bound energy levels of lenslike InAs QD matches well with the experimental results. Moreover the pyramidshaped QD has the greatest difference from the measured experimental data. Keywords Quantum dots PL spectrum Strain QDIP X. -F. Yang . Chen W. Lu National Lab for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences 500 Yutian Road 200083 Shanghai China e-mail xflucky@ W. Lu e-mail luwei@ Y. Fu Department of Theoretical Chemistry School of Biotechnology Royal Institute of Technology AlbaNova Stockholm 106 91 Sweden Introduction Due to three-dimensional confinement for electrons in the quantum-dot structure quantum-dot infrared photodetectors QDIPs have attracted much attention for theoretical and experimental studies in recent years 1-3 . One important characteristic for QDIPs is the sensitivity to normal-incidence infrared .