Impact of built-in fields and contact configuration on the characteristics of ultra-thin GaAs solar cells

Abstract

We discuss the effects of built-in fields and contact configuration on the photovoltaic characteristics of ultrathin GaAs solar cells. The investigation is based on advanced quantum-kinetic simulations reaching beyond the standard semi-classical bulk picture concerning the consideration of charge carrier states and dynamics in complex potential profiles. The thickness dependence of dark and photocurrent in the ultra-scaled regime is related to the corresponding variation of both, the built-in electric fields and associated modification of the density of states, and the optical intensity in the films. Losses in open-circuit voltage and short-circuit current due to leakage of electronically and optically injected carriers at minority carrier contacts are investigated for different contact configurations including electron and hole blocking barrier layers. The microscopic picture of leakage currents is connected to the effect of finite surface recombination velocities in the semi-classical description, and the impact of these non-classical contact regions on carrier generation and extraction is analyzed.

5 pages, 8 figures

References in corpus (3)

• Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
• 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

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• Generalized Reciprocity Relations in Solar Cells with Voltage-Dependent Carrier Collection: Application to p-i-n Junction Devices
• Nonequilibrium theory of the conversion-efficiency limit of solar cells including thermalization and extraction of carriers
• Quantum-kinetic perspective on photovoltaic device operation in nanostructure-based solar cells