High-efficiency GaInP∕GaAs∕InGaAs triple-junction solar cells grown inverted with a metamorphic bottom junction

Abstract

The authors demonstrate a thin, Ge-free III–V semiconductor triple-junction solar cell device structure that achieved 33.8%, 30.6%, and 38.9% efficiencies under the standard 1sun global spectrum, space spectrum, and concentrated direct spectrum at 81suns, respectively. The device consists of 1.8eV Ga0.5In0.5P, 1.4eV GaAs, and 1.0eV In0.3Ga0.7As p-n junctions grown monolithically in an inverted configuration on GaAs substrates by organometallic vapor phase epitaxy. The lattice-mismatched In0.3Ga0.7As junction was grown last on a graded GaxIn1−xP buffer. The substrate was removed after the structure was mounted to a structural “handle.” The current-matched, series-connected junctions produced a total open-circuit voltage over 2.95V at 1sun.

Relaxation dynamics and residual strain in metamorphic AlSb on GaAs

“…Metamorphic InGaAs has been integrated in GaAs based tandems, but requires the growth of thick step graded buffers of InGaP. 1 Here, we present a study on the nucleation and subsequent growth of AlSb on GaAs (001) and compare our results with the more extensively studied case of GaSb on GaAs (Refs. 2 and 3) and the case of AlSb grown on Si.…”

Device characterization for design optimization of 4 junction inverted metamorphic concentrator solar cells

“…Inverted 4J solar cells are grown on GaAs substrates by atmospheric pressure metal organic vapor phase epitaxy and subsequently processed as described previously for 3J IMM solar cells 5 . Adjustable parameters of the design include bandgap through composition and ordering, absorber layer thickness, doping, optical structure such as antireflective coatings and back reflectors, and material quality.…”

Inverted thin film InGaP/GaAs tandem solar cells for CPV applications using epitaxial lift off

“…A third advantage of a thin-film cell is that it can be grown in normal or reverse order which opens new possibilities for cell structures. The ELO process is naturally compatible with the growth and fabrication of an inverted metamorphic multijunction (IMM) cell which has shown itself capable of producing world leading efficiencies under concentration [2]. In the IMM cell the high band gap subcells with the active layers consisting of InGaP and GaAs, are grown lattice matched on the GaAs substrate starting with the highest band gap material.…”