Abstract
We study on the electron transport of an ensemble of coupled sites that simulates an array of quantum dots or a molecular system. By using the Green's function technique, we calculate current and shot noise for linear and disordered site arrays. While in the linear case the characteristic I-V curve reveals no current rectification, in the disordered con- figurations a robust rectification is found, thus indicating an operational regime typical of molecular diodes. Addi- tionally, a negative differential resistance is observed due to the drop of the bias voltage along the structure, which yields to an energy mismatch of neighboring sites. Finally, the Fano factor reveals a stronger transport correlation for positive than for negative bias voltages in the disordered site configuration.
Highlights
One of the major goals in nanoelectronics is the development of diodes and transistors on the scale of the nanocontact size [1, 2]
Based on Green function technique [23], we find a strong current and noise rectification arising from a disordered geometry
Starting with the linear chain configuration, one can clearly see in Fig. 2a, b that the transmission coefficient profiles inside the conduction window (CW) are exactly the same for both direct and reverse bias voltages
Summary
One of the major goals in nanoelectronics is the development of diodes and transistors on the scale of the nanocontact size [1, 2]. Advanced lithographic techniques have allowed the design of quantum dots in semiconductorbased structures, which can operate as a single electron transistor [3]. Bednarek et al, using an effective interaction show that it is possible to find an exact solution for a two-electron artificial molecule in coupled quantum dots [15]. By considering the same coupling to the right and left leads, we exploit the dot arrangement, which mimics a molecular geometry and affects the current. Based on Green function technique [23], we find a strong current and noise rectification arising from a disordered geometry.. A negative differential resistance (NDR) is found for both geometries, which was identified as due to misalignment of the site energies when a source–drain bias voltage is applied
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