AlGaAsP Distributed Bragg Reflectors for GaAsP/Si Solar Cells
Year: 2024
Type: article
Abstract: We investigate (Al)GaAsP distributed Bragg reflectors (DBRs) on Si (001) to improve the quantum efficiency (QE) of 1.7 eV GaAsP solar cells in GaAsP/Si tandem devices. Samples were grown on Si (001) by molecular beam epitaxy and consisted of a 2.1$\mu \mathrm{m}$GaAsP/GaP buffer followed by a ∼2$\mu \mathrm{m}$DBR with 20 periods of GaAsP/AlxGa1-xAsP alternating layers. Two different DBR designs were studied withx= 0.4 andx= 0.8, both targeting a peak reflectance wavelength of 700 nm. The average threading dislocation density on the DBRs was 1.4 × 107cm−2, suitable for high-performance GaAsP cells. The reflectance profiles matched well to simulations, and the GaAsP/Al0.8Ga0.2AsP DBR had a significantly higher peak reflectance and reflectance bandwidth than the GaAsP/Al0.4Ga0.6AsP DBR due to the higher refractive index contrast. QE simulations of GaAsP cells showed an improvement of ∼1 mA/cm2in short-circuit current density with a DBR, which should enable a ∼5% relative efficiency boost in the GaAsP cell and superior current matching to a Si bottom cell in tandem devices.
Source: IEEE Journal of Photovoltaics
Authors: Brian Li, Yiteng Wang, Adrian Birge, Bora Kim, Xizheng Fang, Minjoo Larry Lee
Institution: University of Illinois Urbana-Champaign
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,495
Award: G5498603677
OpenAlex ID: W4404177779