A 19% efficient AlGaAs solar cell with graded band gap

Abstract

An Al0.20Ga0.80As solar cell with a band gap graded from 1.64 eV at the junction to 1.72 eV at the surface has been fabricated using metalorganic chemical vapor deposition. An efficiency of 19.2% has been measured under 1-sun, AM2 simulated conditions with an open circuit voltage of 1.18 V, a short circuit density of 14.5 mA/cm2, and a fill factor of 0.83.

Finite element simulations of compositionally graded InGaN solar cells

“…The design is technologically feasible, as it has been shown that graded In x Ga 1 À x N layers can be grown over the entire composition range using the Energetic Neutral Atom Beam Lithography and Epitaxy (ENABLE) process [20]. Compositional grading in solar cells has previously been considered in the Al x Ga 1 À x As materials system, where it was found to reduce surface recombination losses [21,22]. Grading has also been used in CuIn x Ga 1 À x Se 2 cells to increase the efficiencies in thin devices [23].…”

Assessing material qualities and efficiency limits of III-V on silicon solar cells using external radiative efficiency

“…These are listed in Table . We also calculated the EREs of III–V/Si and III–V solar cells in using this approach. The results are listed in Table .…”

Assessing material qualities and efficiency limits of III-V on silicon solar cells using external radiative efficiency

“…These are listed in Table I. We also calculated the EREs of III-V/Si and III-V solar cells in [15][16][17] using this approach. The results are listed in Table II.…”

“…With these ERE values of each subcell, the limiting efficiency of this 2J cell is 36.5%. Because achieving the quality of state-of-the-art GaAs is still challenging for the candidate 1.73-eV III-V materials, a more realistic estimate is considering a top cell that matches the EREs of the AlGaAs reported in [15] or [16], which are both around 10 -4 . The limiting efficiency of this 2J cell is then 33.9%.…”