Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Metamorphic Tunnel Junctions Grown Via MOCVD Designed for GaAs0.75P0.25/Si Tandem Solar Cells

Journal Article · · IEEE Journal of Photovoltaics
A high-performance metamorphic Al0.2Ga0.8As0.75P0.25/GaAs0.75P0.25 heterojunction tunnel junction structure was developed for application to monolithic epitaxial GaAs0.75P0.25/Si 1.7 eV/1.1 eV bandgap tandem solar cells produced via metal-organic chemical vapor deposition. Doping optimization focused on both bulk doping concentrations and mitigating the transient incorporation effects that otherwise causes non-abrupt doping profiles in the Te doped layer. Furthermore, these efforts resulted in a fully-relaxed metamorphic tunnel diode at the target lattice constant having a peak tunneling current density (JP) of 279.1 A·cm –2 and a zero-bias resistance area product (RA) of 3.0×10 –4 Ω·cm2. After post-growth annealing to emulate the thermal load of the GaAs0.75P0.25 top cell growth and elimination of the performance enhancing carbon activation anneal, the device achieved JP = 13.1 A·cm –2 and RA = 1.5×10 –3 Ω·cm2. These worst-case values are very promising as they enable the operation of GaAs0.75P0.25/Si tandems under one-sun AM1.5G illumination with negligible series resistance and at AM1.5D concentrations up to 240 suns with only 0.1% absolute efficiency loss.
Research Organization:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Grant/Contract Number:
EE0007539
OSTI ID:
1784257
Journal Information:
IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 2 Vol. 11; ISSN 2156-3381
Publisher:
IEEECopyright Statement
Country of Publication:
United States
Language:
English