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Self-consistent finite difference method for simulation and optimization of quantum well electron transfer structures

: Weinert, C.M.; Agrawal, N.


Journal of applied physics 76 (1994), No.12, pp.7947-56
ISSN: 0021-8979
ISSN: 1089-7550
Journal Article
Fraunhofer HHI ()
aluminium compounds; capacitance; finite difference methods; gallium arsenide; gallium compounds; high-speed optical techniques; iii-v semiconductors; indium compounds; leakage currents; optical switches; schrodinger equation; semiconductor device models; semiconductor quantum wells; semiconductor switches; self-consistent finite difference method; quantum well electron transfer structures; InGaAsP/inp/inalas; fast optical switching device; poisson's equation; continuity equation; schrodinger's equation; leakage current; charge distribution; optical absorption edge; band filling; InGaAsP-InP-inalas

A self-consistent finite difference method for the simulation of quantum well electron transfer structures is developed and applied to optimize InGaAsP/InP/InAlAs structures for fast optical switching devices. Simultaneous solution of Poisson's equation, continuity equation, and Schrodinger's equation on a discretized mesh yields a fast and accurate simulation method which may be applied to arbitrary layer structures and needs no artificial assumptions like abrupt space charge layers. Because of the exact treatment of charge distribution and leakage current the simulation gives new insight into the performance of barrier, reservoir, and quantum well electron transfer structures, which could not be found by previous approximate theories. With this method we calculate the important physical parameters of these devices, namely, the shift of the optical absorption edge, band filling, leakage current, and capacitance. In addition, each layer is investigated separately with respect to its influence on device performance and fabrication tolerances; the results are used for optimization. Moreover, the exact numerical simulation is used to derive simplified relations for the dependence of band filling, capacitance, and high speed behavior on the heterostructure design.