Formation of single-crystal Cu2O strips in non-singlecrystal CuO thin films by continuous-wave laser diode with micro-chevron laser beam (μ-CLB)

Crystallization of thin film materials by exploiting laser-induced crystallization has been advancing for the past four decades. This unique thin film technique has pedominantly been used in processing thin film semiconductor materials made of a single chemical element; however, harnessing this technique to extend its use for thin film materials containing multiple chemical elements (e.g., metal oxides) unlocks applications currently not accessible. In this study, laser crystallization of Cu2O strips was demonstrated. A continuous-wave laser diode with a micrometer-scale chevron-shaped beam profile-micro-chevron laser beam (mu-CLB)-was used to form single-crystal Cu2O strips crystallized in CuO thin films covered with an amorphous carbon cap layer and deposited on fused silica substrates. Electron backscatter diffraction, Raman spectroscopy, photoluminescence spectroscopy, and UV-Vis spectroscopy were used to investigate the crystallinity and optical properties of the Cu2O strips, revealing their unique characteristics associated with the crystallization process.