Structure and properties of CaNb2O6:Sm3+ thin films by pulsed laser deposition

CaNb2O6:Sm3+ films were prepared on quartz glass and α-Al2O3(001) substrates by pulsed laser deposition. The structural, morphological, and optical properties of the CaNb2O6:Sm3+ films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), emission-scan electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL) measurements. The results show that the structure and properties of CaNb2O6:Sm3+ films were dependent on substrates. The CaNb2O6:Sm3+ films on Al2O3(0001) substrate have better crystallinity. The full-width at half-maximum (FWHM) of (131) peak are 0.45 and 0.32 for the CaNb2O6:Sm3+ film on glass and Al2O3(001), respectively. The crystallite size of CaNb2O6:Sm3+ films grown on glass and Al2O3(001) was about 8.22 and 9.98 nm, respectively. The oxidation state of the Sm element on the films was Sm3+ state. The photoluminescence (PL) spectra were measured at room temperature, the CaNb2O6:Sm3+ films on Al2O3(001) substrate have a better PL intensity, the identified emission bands were by the intra 4f transitions of Sm3+ from the excited level to the lower levels at 567 nm for 4G5/2→6H5/2 transition, at 609 nm for 4G5/2→6H7/2 transition, and at 657 nm for 4G5/2→6H9/2 transition.