The reliability of III-V solar cell with copper based contacts as low-cost metallurgy option for solar cells including Cu-based Cu/Ge/Pd contact on n-type GaAs and Cu/Pt/Ti/Pt contact on p-type Ge is studied in this paper. The Cu-based contacts have low specific contact resistances of the order of 10(-6) Omega cm(2). The solar cells with the proposed Cu-based structures were subjected to high-temperature annealing (250 degrees C) and a high DC current (6.5 x 10(-4) mA/mu m(2)) stress test. Overall, the solar cell adopting these Cu-based contacts remained quite stable and demonstrated excellent performances after these reliability tests. (C) 2015 Elsevier Ltd. All rights reserved.