Comparative study of 2.05 eV AlGaInP and metamorphic GaInP materials and solar cells grown by MBE and MOCVD

This work investigates 2.05 eV bandgap (Al)GaInP alloys for use as the top junction of IMM solar cells. We explore balancing alloy composition and lattice constant as two complementary variables to achieve the target bandgap in one material system. Here both MBE and MOCVD growth methods are compared to achieve this goal. The specific compositions are Ga
_0.63
In
_0.37
P (tensile relaxed with respect to GaAs) and (Al
_0.13
Ga
_0.38
)
_0.51
In
_0.49
P (lattice matched to GaAs) in order to determine the relative impact of misfit and increased aluminum content, respectively. Prototype solar cell performance and defect spectroscopy (DLTS/DLOS) are used to evaluate the various alloys, and results suggest that MOCVD metamorphic Ga
_0.63
In
_0.37
P is promising for a high performance top cell.