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Title: Numerical simulation of advanced semiconductor devices
Author: Gault, M.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1994
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In this thesis the numerical simulation of advanced semiconductor devices is considered. In order to simulate devices such as the semiconductor laser or the electron wave diffraction transistor advanced physical models must be included. These models are first derived and then applied to particular devices of interest. Initally the fundamentals of heterostructure device modelling are considered with descriptions of the control region approximation and the Scharfetter-Gummel algorithm for the calculation of the current densities. This model is then developed to cope with degenerate statistics using an additional parameter in the Maxwell-Boltzmann exponential. To simulate optical devices such as semiconductor lasers the optical field must be known and hence the solution to the wave equation is considered. Two methods are used, the effective and weighted index methods, and it is found that the weighted index method has important advantages for wave guides of reduced size. In either method a one dimensional algebraic eigenvalue equation must be solved and a highly efficient method for the solution to this equation is presented. The thermal properties of buried heterostructure lasers are investigated using a coupled approach to the electrical, thermal and optical equation sets. The lasing mode profiles, carrier distributions, threshold currents and temperature characteristics are analysed and good agreement is found with experimental results, including the temperature dependence of the threshold current and the prediction of a break-point temperature. To model quantum effects Schröinger's equation is solved using the transfer matrix technique and this is coupled with Poisson's equation and the continuity equations. Scattering is introduced via Lorentzian broadening and a new method for incorporating a finite capture time is derived. This model is applied to 'coherent electron emitters' and a new device is proposed which provides highly coherent emission in the direction of propagation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available