Nonpolar GaAs Nanowires Catalyzed by Cu₅As₂: Insights into As Layer Epitaxy

Controlled synthesis of GaAs nanowires (NWs) with specific phases and orientations is important and challenging, which determines their electronic performances. Herein, single-crystalline GaAs NWs are successfully synthesized by using complementary metal-oxide semiconductor compatible Cu₂O catalysts via chemical vapor deposition at an optimized temperature of 560 °C. In contrast to typically Au catalyzed GaAs NWs, the Cu₂O catalyzed ones are found to grow along nonpolar orientations of zincblende <110> and <211> and wurtzite <1̅100> and <2̅110>. The Cu₂O catalysts are found to change into orthorhombic Cu₅As₂ after the NW growth, which is also significantly distinguished from the Au-Ga catalyst alloy in the literature. The Cu₅As₂ alloy plays the epitaxy role in the nonpolar GaAs NW growth due to the lattice matching with the nonpolar planes of GaAs, which is verified by the atomic stack model. These nonpolar oriented GaAs NWs have minimized stacking faults, promising for the other semiconductor synthesis as well as electronic applications.