title: Erbium emission in MOS light emitting  devices: from energy transfer to direct  impact excitation.
abstract: The electroluminescence (EL) at 1.54 μm of metal–oxide–semiconductor (MOS) devices withEr3C ions embedded in the silicon-rich silicon oxide (SRSO) layer has been investigated under different polarization conditions and compared with that of erbium doped SiO2 layers. EL time-resolved measurements allowed us to distinguish between two different excitation mechanisms responsible for the Er3C emission under an alternate pulsed voltage signal (APV). Energy transfer from silicon nanoclusters (Si-ncs) to Er3C is clearly observed at low-field APV excitation. We demonstrate that sequential electron and hole injection at the edges of the pulses creates excited states in Si-ncs which upon recombination transfer their energy to Er3C ions. On the contrary, direct impact excitation of Er3C by hot injected carriers starts at the Fowler–Nordheim injection threshold (above 5 MV cm(-1)) and dominates for high-field APV excitation.
authors.affiliation: Departament d’Electrònica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona 08028, Spain. jmramirez@el.ub.es
authors.forename: J M
authors.initials: JM
authors.lastname: Ramíırez
authors.forename: F
authors.initials: F
authors.lastname: Ferrarese Lupi
authors.forename: O
authors.initials: O
authors.lastname: Jambois
authors.forename: Y
authors.initials: Y
authors.lastname: Berencén
authors.forename: D
authors.initials: D
authors.lastname: Navarro-Urrios
authors.forename: A
authors.initials: A
authors.lastname: Anopchenko
authors.forename: A
authors.initials: A
authors.lastname: Marconi
authors.forename: N
authors.initials: N
authors.lastname: Prtljaga
authors.forename: A
authors.initials: A
authors.lastname: Tengattini
authors.forename: L
authors.initials: L
authors.lastname: Pavesi
authors.forename: J P
authors.initials: JP
authors.lastname: Colonna
authors.forename: J M
authors.initials: JM
authors.lastname: Fedeli
authors.forename: B
authors.initials: B
authors.lastname: Garrido