Change In Electron Distribution Function Research Articles

Theory of photon-assisted tunneling through quantum dot

Based on the two-channel Anderson Hamiltonian with the non-equilibrium electron distribution under an external electric field, we develop the theory of stationary photon-assisted tunneling current via strongly correlated energy levels in a quantum dot. The non-equilibrium (Mahanthappa–Baksi–Keldysh) Green function formalism is employed to study the Kondo effect and Coulomb blockade phenomenon in the presence of an external field. The Coulomb interaction is treated within the second order perturbation in the self-energy. The change of electron distribution function in the quantum dot due to emission and absorption of photons is taken into account and is found to play a very important role for the suppression of the Kondo effect. We show that an opening of new tunneling channel through photon side band accounts for a Coulomb staircase in the electric current.

Hot-Electron Distribution in n-GaAs Derived from Photoluminescence Measurements with Applied Electric Field

Photoluminescence measurements have been made on thin, epitaxial layers of n-GaAs to which an electric field is applied. Field-dependent spectra are obtained corresponding to band-to-band recombination at 77 and 200°K, and from these the changes in electron distribution function are derived, allowance being made for the distributions of light and heavy holes. A fairly good agreement with theory is obtained, although variations between samples are too great to give clear support to the detailed model of Rees as opposed to the more phenomenologically drifted Maxwellian. The field suppression of the exciton peak is marked and is not adequately explained by present theory.