Theory and simulation of photogeneration and transport in Si-SiOx superlattice absorbers

Abstract

Si-SiOx superlattices are among the candidates that have been proposed as high band gap absorber material in all-Si tandem solar cell devices. Due to the large potential barriers for photoexited charge carriers, transport in these devices is restricted to quantum confined superlattice states. As a consequence of the finite number of wells, large built-in fields and any kind of disorder, the electronic spectrum can deviate considerably from the minibands of a regular superlattice. In this paper, a quantum-kinetic theory based on the non-equilibrium Green's function formalism for an effective mass Hamiltonian is used to investigate photogeneration and transport in such devices for arbitrary geometry and operating conditions. By including the coupling of electrons to both photons and phonons, the theory is able to provide a microscopic picture of indirect generation, carrier relaxation and inter-well transport mechanisms beyond the ballistic regime.

7 pages, 6 figures, submitted to Nanoscale Research Letters, special issue of the EMRS Fall Meeting 2010, Symposium E

Cited by in corpus (11)

• Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
• Quantum-kinetic theory of photocurrent generation via direct and phonon-mediated optical transitions
• Photocarrier extraction in GaAsSb/GaAsN type-II QW superlattice solar cells
• Quantum-kinetic theory of steady-state photocurrent generation in thin films: Coherent versus incoherent coupling
• Simulation of nanostructure-based high-efficiency solar cells: challenges, existing approaches and future directions
• Simulation of nanostructure-based and ultra-thin film solar cell devices beyond the classical picture
• Simulation of Ultra-thin Solar Cells Beyond the Limits of the Semi-classical Bulk Picture
• Effective microscopic theory of quantum dot superlattice solar cells
• Nonequilibrium Green's function theory of coherent excitonic effects in the photocurrent response of semiconductor nanostructures
• Quantum-kinetic perspective on photovoltaic device operation in nanostructure-based solar cells
• Nonequilibrium Green's Function simulation of Cu2O photocathodes for photoelectrochemical hydrogen production