In Situ Local Oxidation of SnO Induced by Laser Irradiation: A Stability Study

In this work, semiconductor tin oxide (II) (SnO) nanoparticles and plates were synthesized at room conditions via a hydrolysis procedure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the high crystallinity of the as-synthesized romarchite SnO nanoparticles with dimensions ranging from 5 to 16 nm. The stability of the initial SnO and the controlled oxidation to SnO₂ was studied based on either thermal treatments or controlled laser irradiation using a UV and a red laser in a confocal microscope. Thermal treatments induced the oxidation from SnO to SnO₂ without formation of intermediate SnO_x, as confirmed by thermodiffraction measurements, while by using UV or red laser irradiation the transition from SnO to SnO₂ was controlled, assisted by formation of intermediate Sn₃O₄, as confirmed by Raman spectroscopy. Photoluminescence and Raman spectroscopy as a function of the laser excitation source, the laser power density, and the irradiation duration were analyzed in order to gain insights in the formation of SnO₂ from SnO. Finally, a tailored spatial SnO/SnO₂ micropatterning was achieved by controlled laser irradiation with potential applicability in optoelectronics and sensing devices.