title: Photoluminescence from silicon nanoparticles embedded in ammonium silicon hexafluoride.
abstract: Silicon (Si) nanoparticles (NPs) were synthesized by transforming a Si wafer surface to ammonium silicon hexafluoride (ASH) or (NH(4))(2)SiF(6) under acid vapor treatment. Si-NPs which were found to be embedded within the polycrystalline (ASH) layer exhibit a strong green-orange photoluminescence (PL). Differential PL measurements revealed a major double component spectrum consisting of a broad band associated with the ASH-Si wafer interfacial porous oxide layer and a high energy band attributable to Si-NPs embedded in the ASH. The origin of the latter emission can be explained in terms of quantum/spatial confinement effects probably mediated by oxygen related defects in or around Si-NPs. Although Si-NPs are derived from the interface they are much smaller in size than those embedded within the interfacial porous oxide layer (SiO(x), x > 1.5). Transmission electron microscopy (TEM) combined with Raman scattering and Fourier transformed infrared (FTIR) analysis confirmed the presence of Si-NP and Si-O bondings pointing to the role of oxygen related defects in a porous/amorphous structure. The presence of oxygen of up to 4.5 at.% in the (NH(4))(2)SiF(6) layer was confirmed by energy dispersive spectroscopy (EDS) analysis.
authors.affiliation: UEKAE, National Research Institute of Electronics and Cryptology, Kocaeli, Turkey. s.kalem@uekae.tubitak.gov.tr
authors.forename: Seref
authors.initials: S
authors.lastname: Kalem
authors.forename: Peter
authors.initials: P
authors.lastname: Werner
authors.forename: Vadim
authors.initials: V
authors.lastname: Talalaev
authors.forename: Michael
authors.initials: M
authors.lastname: Becker
authors.forename: Orjan
authors.initials: O
authors.lastname: Arthursson
authors.forename: Nikolai
authors.initials: N
authors.lastname: Zakharov