The effect of annealing temperatures on morphologies and photoluminescence properties of terbium-doped SiCN films

Terbium-doped SiCN (SiCN:Tb) films were prepared by radio frequency (rf) reactive sputtering at room temperature (RT) and then annealed in a carbothermal ambience at 800 and 1250 °C, respectively. The RT prepared and 1250 °C annealed samples have shown blue–green and blue–violet light emissions, respectively; whereas strong green light emissions were observed only from the 800 °C annealed samples. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) results revealed that the change of PL properties can be attributed to the evolution of microstructure and chemical compositions of the SiCN films. In addition, photoluminescence excitation (PLE) spectrum indicated that the best PL performance of the 800 °C annealed samples might be mainly attributed to the direct band gap (about 3.81 eV) of crystalline SiCN.