title: Electroluminescence microspectroscopy of silicon nanocrystals obtained by Si(+) ion implantation in SiO(2).
abstract: Room-temperature electroluminescence (EL) has been measured at both macroscopic and microscopic levels from metal-oxide-semiconductor devices containing silicon nanocrystals (Si-nc) embedded in silicon dioxide (SiO(2)) obtained by high-temperature annealing (1050 and 1100 °C) after Si(+) ion implantation. It is found that spatially integrated (macroscopic) EL is dominated by a near-infrared band centered where the photoluminescence (PL) band of Si-nc (from 700 to 1000 nm) is located. However, on a microscopic scale, EL emission is inhomogeneous, the sample surface exhibiting many visible spots of micron-order diameter. EL spectra from a microscopic surface of ∼1 µm(2)(μEL) on visible spots have revealed dominant contributions between ∼550 and ∼650 nm, attributed to oxide defects. These spectral features rapidly decrease with distance from a bright spot, while lower-intensity near-infrared contributions (750-950 nm) remain unaffected up to relatively large distances before eventually becoming extinct. The macroscopic EL measurements can be explained as a superposition of the μEL and PL spectra. A luminescent mechanism is proposed in which charge carriers mostly tunnel through high-defect-density channels in the oxide, yielding bright visible spots, while Si-nc in these channels and their surroundings contribute to the luminescence by hosting electron-hole recombinations (EL) and/or exhibiting PL due to optical excitation from the nearby visible EL spot.
authors.affiliation: INRS-Énergie, Matériaux et Télécommunications, 1650 boulevard Lionel-Boulet, Varennes QC, J3X 1S2, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Lacombe
authors.forename: B
authors.initials: B
authors.lastname: Kadari
authors.forename: F
authors.initials: F
authors.lastname: Beaudoin
authors.forename: D
authors.initials: D
authors.lastname: Barba
authors.forename: F
authors.initials: F
authors.lastname: Martin
authors.forename: G G
authors.initials: GG
authors.lastname: Ross