Nanomaterials @ Interfaces Research Group

Epitaxial cuprous oxide (Cu₂O) thin films were deposited from aqueous alkaline solutions within confined microsquares in micropatterned GaAs. Raman spectroscopy and transmission electron microscopy analysis revealed the presence of single-phase Cu₂O, with no detectable CuO impurity. In contrast to (110) textured polycrystalline Cu₂O films obtained on unpatterned substrates, monocrystalline Cu₂O (100) films were obtained within the GaAs microsquares. It was found that a 45° in-plane rotation of the prefabricated microsquares with respect to the [01̅1] GaAs axis promotes Cu₂O (100) monocrystalline growth by minimizing lattice mismatch and providing optimal substrate/film orientation for growth. The thickness of the Cu₂O film and the growth rate within the confined squares emerge as dominant parameters affecting crystal quality and controlling photoluminescence emission, as evidenced by formation of point defects, primarily oxygen vacancies.