title: Structural dependences of localization and recombination of photogenerated carriers in the top GaInP Subcells of GaInP/GaAs double-junction tandem solar cells.
abstract: In high-efficiency GaInP/GaAs double-junction tandem solar cells, GaInP layers play a central role in determining the performance of the solar cells. Therefore, gaining a deeper understanding of the optoelectronic processes in GaInP layers is crucial for improving the energy conversion efficiency of GaInP-based photovoltaic devices. In this work, we firmly show strong dependences of localization and recombination of photogenerated carriers in the top GaInP subcells in the GaInP/GaAs double-junction tandem solar cells on the substrate misorientation angle with excitation intensity- and temperature-dependent photoluminescence (PL). The entire solar cell structures including GaInP layers were grown with metalorganic chemical vapor deposition on GaAs substrates with misorientation angles of 2° (denoted as Sample 2°) and 7° (Sample 7°) off (100) toward (111)B. The PL spectral features of the two top GaInP subcells, as well as their excitation-power and temperature dependences exhibit remarkable variation on the misorientation angle. In Sample 2°, the dominant localization mechanism and luminescence channels are due to the energy potential minima caused by highly ordered atomic domains; In Sample 7°, the main localization and radiative recombination of photogenerated carriers occur in the atomically disordered regions. Our results reveal a more precise picture on the localization and recombination mechanisms of photogenerated carriers in the top GaInP subcells, which could be the crucial factors in controlling the optoelectronic efficiency of the GaInP-based multijunction photovoltaic devices.
authors.affiliation: Department of Physics, HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong , Pokfulam Road, Hong Kong, China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Deng
authors.forename: Jiqiang
authors.initials: J
authors.lastname: Ning
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Su
authors.forename: Shijie
authors.initials: S
authors.lastname: Xu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xing
authors.forename: Rongxin
authors.initials: R
authors.lastname: Wang
authors.forename: Shulong
authors.initials: S
authors.lastname: Lu
authors.forename: Jianrong
authors.initials: J
authors.lastname: Dong
authors.forename: Baoshun
authors.initials: B
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
keywords: GaInP/GaAs double-junction tandem solar cells; localization mechanism; photoluminescence; radiative recombination