title: Tailored nanoheterojunctions for optimized light emission.
abstract: We present coupled classical and quantum simulations of 1 to 2 nm Si nanocrystals (NCs) embedded in amorphous SiO(2) and we show that by tuning the density of the oxide matrix one may change the relative alignment of Si NC and SiO(2) electronic states at the interface. We find that interfacial strain plays a key role in determining the variation of the nanaoparticle gap as a function of size, as well as of conduction band offsets with the oxide. In particular, our results show that it is the variation of the valence band offset with size that is responsible for the gap change. Our findings suggest that the elastic properties of the embedding matrix may be tuned to tailor the energy levels of small Si NCs so as to optimize their performance in optoelectronic devices and solar cells.
authors.affiliation: Department of Civil and Environmental Engineering, George Washington University, Washington, DC 20052, USA. tsli@gwu.edu
authors.forename: Tianshu
authors.initials: T
authors.lastname: Li
authors.forename: Francois
authors.initials: F
authors.lastname: Gygi
authors.forename: Giulia
authors.initials: G
authors.lastname: Galli