Heterosubstrate Illumination Effects in III–V Solar Cells

Le résumé fourni par la source

Reference cell based current vs voltage (IV) measurements assume that the effect of an illumination spectrum on a solar cell's performance can be fully captured by the multiplication of the spectrum with the device's spectral response and subsequent integration. This is based on a fundamental understanding that sub-bandgap light will be minimally absorbed, if at all, in the active layers of the solar cell and therefore not contribute to the power generation. In this work we show a novel phenomenon in which illumination of the substrate is required for good performance in solar cells with III-V active layers and germanium substrates, despite negligible contribution to the short circuit current or open circuit voltage, or increase of generated power beyond that expected from the III-V junction. Discovered in the course of characterizing cells for low-light conditions, we confirm the observation with additional IV and electroluminescence measurements and modeling that reproduces experimental results. This phenomenon has implications for device characterization under non-standard light sources, the development of solar cells for conditions lacking long-wavelength light such as indoor photovoltaics under light-emitting diode illumination, and the prediction of device performance under spectra that differ from the test conditions.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.