Inverted metamorphic InGaAsP/InGaAs dual-junction solar cells towards full solar spectrum harvesting. Issue 24 (13th June 2022)

• Record Type: Journal Article
• Authors: Park, Suho; McCartney, Martha R.; Smith, David J.; Jeon, Jiyeon; Kim, Yeongho; Lee, Sang Jun
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 24(2022)
• Page Start: 13106
• Page End: 13113
• Publication Date: 2022-06-13
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta01603f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An InGaAsP (1.04 eV)/InGaAs (0.54 eV) dual-junction solar cell, monolithically grown in an inverted configuration on an InP substrate, has been demonstrated. Abstract : An InGaAsP (1.04 eV)/InGaAs (0.54 eV) dual-junction solar cell, monolithically grown in an inverted configuration on an InP substrate, has been demonstrated. Five metamorphic compositionally graded buffers of InAs x P1− x are used to transition from the InP lattice constant to that of the In0.74 Ga0.26 As bottom cell. The InAs0.45 P0.55 buffer, lattice-matched to In0.74 Ga0.26 As, has a surface crosshatch pattern with an rms roughness of 2.1 and 4.7 nm along the in-plane [110] and [11̄0] directions, respectively, due to different lateral growth rates under high As pressure. Cross-section observations using transmission electron microscopy indicate a major reduction in the density of misfit and threading dislocations across the metamorphic InAs x P1− x structure. The formation of crystalline defects in the n + -InAsP buffers induces a strain relaxation of ∼95% in the bottom cell with a relaxed lattice constant of 5.9563 Å. The reverse saturation current and ideality factor of the bottom cell are increased because of enhanced nonradiative recombination at threading dislocations with a density of 2 × 10 6 cm −2 . Under AM 1.5G illumination, the dual-junction solar cell with extended absorption wavelengths up to 2400 nm has a photovoltaic conversion efficiency of 5.49% with an open-circuit voltage of 0.70 V, a short-circuit current density of 9.86 mA cm −2, and a fill factor of 80.12%.