Following that idea of combining one-dimensional and zero-dimensional nanostructures, like in photonics devices, we investigated the photovoltaic response of a mesoscopic junction in which the light is absorbed in a quantum dot laterally connected to two quantum wires on each side Fig. 1. The transport and optical properties have then been determined using a powerful methodology for quantum statistics, the non-equilibrium Green function formalism. We thus examined how tunneling and optical coupling interplays in the interacting dot connected to the wires.
Fig.1: Schematics of the quantum junction.
Fig.2: Short-circuit photocurrent mapping as a function of the tunneling and optical couplings
We showed Fig. 2 that the photocurrent is a non-monotonic function of the tunneling parameter. As a major consequence the photocurrent changes its monotonicity under bias depending on the optical versus tunneling coupling value. Simulated I-V responses under monochromatic illumination thus show a special shape at resonance: the photocurrent in biased nanowire-quantum dot photovoltaic junctions increases if the tunneling coupling decreases, originating in an reduced absorption.
Authors : A. Berbezier, F. Michelini
Thin solid films (2012)
Journal of Quantum Computational Electronics (2013)
Journal of Renewable Energy (submitted 2013)
Journal of Applied Physics (submitted 2013)