High-efficiency (21.4%) Ga0.75In0.25As/GaAs (E g=1.15 eV) concentrator solar cells and the influence of lattice mismatch on performance

Abstract

High-efficiency Ga0.75In0.25As/GaAs concentrator solar cells (Eg=1.15 eV, area=0.32 cm2) have been fabricated and tested at 21.4% efficiency under 380 AM2.4 sun. The cell performance parameters of open-circuit voltage, fill factor, and efficiency are presented as functions of concentration up to 987 sun. The spectral response, and current-voltage characteristics under concentration, of cells grown by organometallic vapor phase epitaxy on graded and ungraded lattice-constant buffer layers are compared. It is shown that a graded lattice-constant buffer layer is necessary for high-efficiency performance. In general, Ga0.75In0.25As cells have higher efficiencies and open circuit voltages than Si cells (Eg=1.11 eV) for concentrations in excess of about 200 sun.

High-efficiency metamorphic GaInP/GaInAs/Ge solar cells grown by MOVPE

“…A more optimal approach is to lower the bandgaps of both epitaxial subcells, thus balancing the current generated in each subcell, by a latticemismatched, or metamorphic (MM), design [4][5][6][7][8]. One such design is shown schematically in Fig.…”

“…As the bandgaps of both subcells decrease, the current generated increases proportionately and the voltage decreases. Many previous authors have explored the impact of such metamorphic designs for 3J III-V solar cells [4][5][6][7][8].…”

III‐V Solar Cells

“…GaAs substrates: Recognising that AlGaAs or InGaP alloys can be used to make latticematched top cells on a GaAs substrate, there has been a long-standing effort to develop good-quality relaxed InGaAs subcells and early cells delivered promising results [118][119][120]. However, integration of the sub-cells into a monolithic stack proved challenging since the preferred AlGaAs/GaAs/InGaAs architecture in the late 1980s required two graded mismatched layers.…”

The Role of doping in the window layer on Performance of a InP Solar Cells USING AMPS-1D

“…A description of both modes can be found in the AMPS manual [4]; In essence, the lifetime mode accepts inputs in the form of carrier lifetimes, which are assumed constant, independent of light and voltage bias, and does not address the underlying recombination processes. The DOS mode allows the definition of multiple defect states, using densities, energy distributions, and capture cross-sections.…”

“…In this simulation the required parameters of Ga0.1In0.9P window having a hole doping concentration10 20 ( −3 ). Twere taken from the elsewhere [4]. For the rest of the layers the standard parameters were used.…”