Exploring the radiative limits of dark current operation in InGaAs quantum well solar cells

Abstract

While radiative recombination is a well-known intrinsic loss mechanism in photovoltaic devices, nonradiative recombination mechanisms typically dominate compound semiconductor diode currents and limit the performance of even state-of-the-art devices. However, recent advances in device structure design have allowed quantum well structures to begin reaching the radiative limits of dark current operation. In this work, a novel extended heterojunction structure is employed in InGaAs quantum well devices to reduce non-radiative recombination and expose the limiting n=1 radiative component of the diode current. Short circuit current versus open circuit voltage curves derived from illuminated currentvoltage measurements indicate that the underlying dark diode currents of the InGaAs quantum well devices vary with well thickness and emission energy. Analysis of the extracted n=1 saturation current densities indicate that these high-voltage InGaAs quantum well devices are operating in a regime of suppressed radiative recombination.