Two-band combined model of a resonant tunneling diode
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ICS OF SEMICONDUCTOR DEVICES
Two-Band Combined Model of a Resonant Tunneling Diode I. I. Abramov^, I. A. Goncharenko, and N. V. Kolomeitseva Belarussian State University of Informatics and Radioelectronics, ul. Brovki 17, Minsk, 220013 Belarus ^e-mail: [email protected] Submitted August 24, 2006; accepted for publication March 27, 2007
Abstract—A two-band combined model of a resonant tunneling diode, based on the semiclassical and quantum mechanical (the wave function formalism) approaches is proposed. The main specific feature of this model is the possibility of taking into account the interaction between different classical or quantum mechanical device regions with simultaneous consideration of the Γ–X intervalley scattering. It is shown that this model gives satisfactory agreement with the experimental data on the current–voltage characteristics and allows explanation of the plateau region in these characteristics within the stationary model. PACS numbers: 73.40.Gk, 68.65.Cd DOI: 10.1134/S106378260711019X
1. INTRODUCTION Analysis of modern investigations of the physics of resonant tunneling diodes (RTDs) shows that their operation may be significantly affected by the features of the band structure. For example, it was revealed in [1] that in GaAs/AlxGa1 – xAs (0.4 < x < 1) structures the probability of transmission of electrons depends on their states in the Γ and X valleys and the interaction between them. For this reason, a number of two-band models of resonant tunneling structures have been developed, which take into account the effect of Γ–X intervalley scattering [1–3]. The class of two-band models also includes models taking into account electron transfer in the conduction and valence bands. Such models are generally used to calculate the electrical characteristics of resonant tunneling structures with interband tunneling. Within the wave function formalism, a number of models have been developed on the basis of the pseudopotential, tight-binding, and envelope-function methods [4]. The simplest model taking into account the electron transfer in the conduction and valence bands is the Kane model [5, 6], which considers the dynamics of charge carriers in the conduction band and near the top of the valence band in the absence of degeneracy. A drawback of this model is the presence of coupling between the bands in the description of interband tunneling, even in the absence of an external electric field; this property hinders physical interpretation of the results obtained [7]. Two-band models, unfortunately, use a simplified description of the valence band [8]. More complex models are three-band ones, which describe the electron transfer in the Γ1, X1, and X3 valleys [9–12]. In this case, the effect of other valleys is assumed to be negligible.
Even more complex multiband models can be applied within the wave function formalism; however, the boundary conditions are significantly more complicated in this case. In addition to the wave function formalism, the formalisms of the Wigner [13] and Green’s [14–16]
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