Self-formed thin buffer layer assisted growth of MgZnO nanowall structures on GaAs substrates

This study reports the growth of MgZnO nanowall structures on GaAs substrates through the incorporation of Mg by metalorganic chemical vapor deposition at a growth temperature of 500 °C. Through Mg incorporation, a 5 nm-thick MgGa₂O₄ layer was initially self-formed on GaAs substrates, which acted as a buffer layer with reduced lattice mismatch for nanowall growth. However, due to the large difference in lattice parameters, the MgZnO seed crystals grew on the MgGa₂O₄ layer with a pyramidal shape showing a Volmer-Weber growth mode. Moreover, by the random motion of the adatoms on these MgZnO seed crystals, nanowalls with high crystalline quality were grown along the grain boundaries in the MgZnO seed crystals. On the basis of the microstructural characterization of the synthesized nanowall structures, the growth evolution of the MgZnO nanowall structures on GaAs substrates was first proposed.