Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/34681
Title: The novelty and surface-to-volume-ratio dependent electron band structure in semiconductor nanowire
Authors: YAO DONGLAI
Keywords: Silicon Nanowire, DFTB, SVR, Band Gap, Universal expression, Effective Mass
Issue Date: 20-Oct-2011
Source: YAO DONGLAI (2011-10-20). The novelty and surface-to-volume-ratio dependent electron band structure in semiconductor nanowire. ScholarBank@NUS Repository.
Abstract: In the field of nanotechnology, we focus this thesis on the novelty and surface-to-volume ratio dependent electronic band structure in semiconductor nanowires by means of first principle calculation. Silicon nanowires (SiNWs) in [110] growth direction is main research object, whose cross-sectional geometrics and surface-to-volume ratio dependence on the electronic band gap, effective mass are covered in this thesis. We have found that there is a universal band gap expression which is only related to surface-to-volume ratio for nanowires with dimension up to 7 nm. Most interestingly, this expression is a linear dependence of band gap on surface-to-volume ratio, which is independent of the specific cross sectional shape. We also explore the electron effective mass of [110] silicon nanowires with different cross sectional shapes. We found that the electron effective mass decreases with the SiNW transverse dimension (cross sectional area) increases. With the same cross sectional area, the triangular cross section SiNW has larger electron effective mass than that of rectangular cross section SiNW. We also trying to find the direct to indirect band gap transition in [110] SiNWs. We successfully estimated the critical dimension where this direct-indirect band gap transition takes place by using the gauge of SVR and the DFT calculation results. It is found that tri-SiNW has the largest transition dimension up to 14 nm in diameter.
URI: http://scholarbank.nus.edu.sg/handle/10635/34681
Appears in Collections:Ph.D Theses (Open)

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