Structural and optical properties of erbium-doped Ba_0.7Sr _0.3TiO₃ thin films

Er-doped Ba0.7 Sr0.3 Ti O3 (BST:Er) thin films prepared by the sol-gel technique have been investigated by means of x-ray diffraction (XRD), Raman, spectroscopic ellipsometry, Capacitance-voltage, and photoluminescence (PL) measurements. XRD results indicate that the film possess the highest degree of crystallinity at the annealing temperature of 700 °C. The dependence of the refractive index on erbium concentration was also analyzed. In addition, the excitation-dependent PL studies indicate that the green emission peaks do not shift with the change in excitation power, while the integrated intensity increases monotonically with the increase in excitation power. The quenching mechanism of the green emission due to dopant concentrations and annealing temperatures was discussed in detail. All experimental results indicate that BST:Er thin films might be a potential candidate for optoelectronics devices.