Figure 1

Schematic illustration of QD-QW system. Single electron levels of QD are shown by the solid line, while the two electron level is shown by the dotted line. The first excited single electron level of the QD coincides with the size quantization level of QW. The states in the left (right) lead are in quasiequilibrium, which is characterized by chemical potential ${\mu }_L$ $\left({\mu }_R\right)$.Reuse & Permissions

Figure 2

Current vs source-drain voltage (chemical potential of the left lead) is shown for the spinless system for ${\gamma }_L=3$, ${\gamma }_R^{\left(nr\right)}=1$, ${\gamma }_R^{\left(r\right)}=10$, and (a) for $u=10$ and various intensities of the photon flux, where the numbers next to the lines are the values of $w_{\lambda }$; (b) for $w_{\lambda }=5$ and various Coulomb repulsion energies $u$, where the numbers next to the lines are the values of $u$. Here $({\mu }_R-{ϵ}_2)∕kt=-10$ and ${ϵ}_1={ϵ}_2-20\mathrm{kT}$. Even at zero-bias voltage $[({\mu }_R-{ϵ}_2)∕\mathrm{kT}=-10]$ there is a finite current through the system at $w_{\lambda }$. This is due to asymmetry in the tunneling rates, i.e., the excited state of QD is preferably depleted to the right lead whereas the ground state of QD is preferable filled from the left lead. For $w_{\lambda }>0$ the phonons provide the energy to pump electrons from the ground into the excited states of QD.Reuse & Permissions

Figure 3

Current vs source-drain voltage is shown for different intensities of the photon flux for the electron system with a spin. The dimensionless parameters are $u=10$, ${\gamma }_L=3$, ${\gamma }_R^{\left(nr\right)}=1$, and ${\gamma }_R^{\left(r\right)}=10$. The numbers next to the lines are the values of $w_{\lambda }$.Reuse & Permissions