Influence of the metal contact size on the electron dynamics and transport inside the semiconductor heterostructure nanowire

In this paper, modeling of the transport phenomena inside a nanowire is the central issue. In particular, we present numerical results for a GaAs/AlGaAs semiconductor heterostructure nanowire obtained by a 2D numerical simulation based on a transient quantum drift-diffusion model. The model itself is based on the density-gradient theory proposed by Ancona et al. Due to considering angular-symmetric solutions only, two cylindrical coordinates (r and z) suffice for the investigation. Two different numerical implementations of the model employing the finite difference method and finite element method have been used. Influence of the metal contact size on the carrier dynamics and transport inside the nanowire has been investigated. Current-Voltage (I-V) characteristics for the same heterostructure nanowire supplemented with different combinations of the metal contacts of different sizes are presented and discussed. It has been demonstrated that the size of the metal contacts strongly influences the carrier dynamics and I-V characteristics of the heterostructure nanowire and that it is possible to produce and tune N-shape of the I-V characteristics by changing the size of the metal contacts. This is of interest in relation to optimization of I-V characteristics of resonant tunneling nanostructures.

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