Browsing by Subject "Semiconductor device models"

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Open Access
Hydrodynamic approach for modelling transport in quantum well device structures
(Institute of Physics Publishing Ltd., 1998) Besikci, C.; Tanatar, Bilal; Sen, O.
A semiclassical approach for modelling electron transport in quantum well structures is presented. The model is based on the balance equations governing the conservation of particle density, momentum and energy with Monte Carlo (MC) generated transport parameters. Three valleys of the conduction band, size quantization in the Γ valley, and the lowest two subbands in the quantum well are considered by taking the detailed intersubband dynamics into account. The transport parameters of the model are extracted from steady-state MC simulations based on an improved formulation of two-dimensional polar optical phonon scattering including screening effects. The predictions of the proposed model have been found to be in excellent agreement with those of the ensemble MC simulations under both time varying and spatially nonuniform fields. The calculated transport parameters which are of interest for device modelling are presented as a function of the electron energy for the AIGaAs/GaAs quantum well. The model serves as an accurate semiclassical alternative to costly ensemble MC simulations for studying the transport in quantum well structures and for the modelling and optimization of submicron devices based on these structures, such as modulation doped field-effect transistors (MODFETs).
Open Access
Simplified calculations of band-gap renormalization in quantum-wells
(Academic Press, 1996) Güven, K.; Tanatar, Bilal
Non-linear optical properties of photoexcited semiconductor quantum-wells are of interest because of their opto-electronic device application possibilities. Many-body interactions of the optically created electrons and holes lead to the band-gap renormalization which in turn determines the absorption spectra of such systems. We employ a simplified approach to calculate the band-gap renormalization in quantum-well systems by considering the interaction of a single electron-hole pair with the collective excitations (plasmons). This method neglects the exchange-correlation effects but fully accounts for the Coulomb-hole term in the single-particle self-energy. We demonstrate that the density, temperature, and well-width dependence of the band-gap renormalization for GaAs quantum-wells within our model is in good agreement with the experimental results. © 1996 Academic Press Limited.