Photoluminescence from Si nanocrystals induced by high-temperature implantation in $SiO2$

A systematic study of photoluminescence (PL) behavior of Si nanocrystals in $SiO2$ obtained by ion implantation in a large range of temperatures (−200 up to 800 °C), and subsequent furnace annealing in $N2$ ambient was performed. A PL signal in the wavelength range 650–1000 nm was observed. The PL peak wavelength and intensity are dependent on the fluence, implantation and annealing temperatures. It was found that after annealing at 1100 °C, both implantations of $1.5×1017 Si/cm2$ at room temperature or $0.5×1017 Si/cm2$ at 400 °C result in the same PL peak intensity. By varying the implantation temperature we can achieve the same PL efficiency with lower fluences showing that hot implantations play an important role for initial formation of the nanocrystals. The PL intensity evolution as a function of the annealing time was also studied. As the implantation temperature was increased, larger mean size Si nanocrystals were observed by means of dark-field transmission electron microscopy analysis.