Neighbouring Levels Statistic and Shape of Quantum Dots: Si/Sio2

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We model the Si quantum dots (QDs) embedded into the SiO2 substrate. Single sub-band effective mass approach is used to calculate energy levels of electrons and heavy holes. For weak confinement regime (QD size D >10 nm), when number of confinement levels is limited by several hundred, we considered statistical properties of the electron confinement. In particularly to determine the type of the nearest neighbor spacing (NNS) statistics, the distribution function is calculated. The influence of the QD shape on the NNS distribution is investigated. The conditions for changing type of statistics are determined. The Brody formula is applied. Variations of the Brody parameter for different QD shapes are evaluated. Obtained results are discussed. Also we study the possibility of dependence of the statistics on electron effective mass ratio m*(||) / M*(_|_) (which is equal 4.8 for Si). To test the model, which we are using, comparison with available experimental PL exciton data is done. Calculations of low-lying single electron and hole energy levels are performed for spherical shaped QD with diameter D

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Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2010: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational
Published: June 21, 2010
Pages: 25 - 28
Industry sector: Sensors, MEMS, Electronics
Topics: Nanoelectronics
ISBN: 978-1-4398-3402-2