Study on luminescence quenching of ultra-small silicon nanocrystals due to boron doping

Abstract

The doping effect and mechanism on optical property of Si nanocrystals is particularly an interesting issue in order to further broaden their applications in the next generation of electronic and optoelectronic devices. A quenching of photoluminescence in B-doped Si nanocrystals was reported before and there is no consensus on the mechanism. Herein, we fabricate boron-doped Si nanocrystals/SiO2 multilayers with the ultra-small dot sizes near 3.0 nm. It’s found B dopants exhibit a low doping efficiency in ultra-small Si nanocrystals, and are mainly located at the surfaces regions. Electron spin resonance results manifest B dopants lead to defects in Si nanocrystals/SiO2 multilayers, which transform from Pb centers to EX centers. The EX centers, rather than Auger recombination, cause the reduction on the intensities and lifetimes of 840 nm near-infrared emission. Our results give an insight into luminescence quenching of ultra-small Si nanocrystals due to boron doping.