Size dependence of Pb-type photoluminescence quenching defects at the Si nanocrystal interface

Size-controlled Si nanocrystals (nc's) of similar to 2 to 5 nm diameter embedded in amorphous (a-)SiO2 are extensively studied by electron spin resonance (ESR) and photoluminescence (PL). The PL quenching P-b-type (Si dangling bond) interface defects -P-b(0) and P-b1 centers-are investigated as a function of Si nc's size and effective interface area with the embedding SiO2. It is shown that the effective areal P-b-type defect density at the nc-Si/SiO2 interface remains approximately constant, indifferent of the nc size. While Si nc's larger than approximate to 3.5 nm are found to house, on average, at least one PL quenching P-b-type defect, about 75% of the as-annealed 2 nm Si nc's appear P-b-free. Additional study on the effect of heat treatment in H-2 indicates this step to be more efficient in inactivating P-b(0) than P-b1 for all Si nc sizes. Copyright (C) EPLA, 2011