Estudio de la cristalización de Cu$_{2}$O y su caracterización por difracción de rayos X, espectroscópica Raman y fotoluminiscencia

Abstract

The growth of polycrystalline cuprous oxide (Cu$_{2}$O) foils with great single-crystalline areas by the secondary crystallization method from polycrystalline copper in dry air atmosphere is reported. The method comprises two stages; in the first one polycrystalline copper foils were converted in cuprous oxide at 1020$^{\circ}$C by some hours depending of their thickness, in the second stage the growth of great crystalline areas are promoted by annealing the Cu$_{2}$O foils at temperatures near to 1100$^{\circ}$C by extended periods. The growth kinetics of the crystallites was studied; X-ray diffraction (XRD), Raman spectroscopy scattering and photoluminescence (PL) measurements were done as a function of the crystallization conditions. The XRD and Raman scattering measurements reveal the existence of pure Cu$_{2}$O phase. The PL spectra taken from 10 to 180K define the main paths of the radiative recombination processes. Besides of the excitonic transition X$^{o}$ at 610 nm, three strong bands at 720, 810 and 920 nm associated with relaxed excitons at oxygen and copper vacancies, respectively was detected. The relative intensity of the PL transitions of excitons at vacancies change according to the duration of the crystallization process.