Large-area, epitaxial lift-off, inverted metamorphic solar cells

Abstract

Large area (20 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) epitaxial lifted-off (ELO) triple junction (TJ) solar cells based on inverted metamorphic (IMM) InGaP/GaAs/InGaAs were fabricated. These TJ IMM ELO solar cells exhibited efficiency >;29% at one sun AMO illumination, which is the highest reported efficiency for IMM ELO thin cells to date. The cells had fill factor >;85%, open circuit voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> ) = 2.93 V, and short circuit current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> ) = 16.3 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Studies performed on IMM ELO solar cells after >;700 thermal cycles between -175 °C and 80 °C revealed no degradation in cell performance. Batches of up to 48 substrates were subjected to reclaim after the ELO process; no degradation in performance was noted between cells grown on prime and reclaimed substrates.