Fabrication and simulation of GaInAs Solar cells using compositionally step-graded AlGaInAs buffers on GaAs substrate

Abstract

In the direction of the industrial application of invert metamorphic GaInAs/AlGaInAs/GaAs/GaInP quadruple junction solar cells, another 0.67 eV band gap lattice-mismatched GaInAs junction was added into the three-junction 1.8/1.4/1.0 eV solar cells. In this paper, we performed an investigation of a 0.67 eV-GaInAs solar cell on the compositionally step-graded InP/AlGaInxAs/GaAs virtual substrate in order to identify the metamorphic buffers qualities after growing the solar cell. The transmission electron microscopy, X-ray diffraction and atomic force microscope were carried out to analyze material structure properties. The high surface roughness is observed and a region where a significant number of external dislocations are formed in the InGaAs tunnel junction of solar cells is identified. The I–V and EQE characterizations of metamorphic 0.67 eV InGaAs solar cell were measured under 1 sun AM1.5D conditions. To research the impact of threading dislocation densities on the InGaAs solar cell, the simulation results of I–V and EQE have also been discussed with Crosslight APSYS’s some applicable features.