Analysis of perimeter recombination in the subcells of GaInP/GaAs/Ge triple‐junction solar cells

Abstract

Abstract This paper studies the recombination at the perimeter in the subcells that constitute a GaInP/GaAs/Ge lattice‐matched triple‐junction solar cell. For that, diodes of different sizes and consequently different perimeter/area ratios have been manufactured in single‐junction solar cells resembling the subcells in a triple‐junction solar cell. It has been found that neither in GaInP nor in Ge solar cells the recombination at the perimeter is significant in devices as small as 500 μ m × 500 μ m(2.5 ⋅ 10 − 3 cm 2 ) in GaInP and 250 μ m × 250 μ m (6.25 ⋅ 10 − 4 cm 2 ) in Ge. However, in GaAs, the recombination at the perimeter is not negligible at low voltages even in devices as large as 1cm 2 , and it is the main limiting recombination factor in the open circuit voltage even at high concentrations in solar cells of 250 μ m × 250 μ m (6.25 ⋅ 10 − 4 cm 2 ) or smaller. Therefore, the recombination at the perimeter in GaAs should be taken into account when optimizing triple‐junction solar cells. Copyright © 2014 John Wiley & Sons, Ltd.