Blue photoluminescence and local structure of Si nanostructures embedded in SiO2 matrices

Zhang, Qi; Bayliss, S. C.; Hutt, D.A.

doi:10.1063/1.113296

Cited by 124 publications

(49 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of nitrogen in a system of Si clusters embedded in SiO 2 has been identified by x-ray photoelectron spectroscopy. 26 There is also the possibility that some oxygen atoms could decorate the interfacial voids, similarly lowering the S parameter. We should be also aware of the implantation-induced volume compaction in the structure of SiO 2 .…”

Section: Discussionmentioning

confidence: 99%

Characterization of the interface region during the agglomeration of silicon nanocrystals in silicon dioxide

Pi¹,

Coleman²,

Harding³

et al. 2004

Journal of Applied Physics

View full text Add to dashboard Cite

Si nanocrystals embedded in thermally grown SiO 2 have been annealed at temperatures between 400 and 900°C in a variety of atmospheres. Positron annihilation spectroscopy has been employed to study changes in the interface regions between nanocrystalline Si ͑nc-Si͒ and SiO 2 with the support of photoluminescence measurements. We find that nitrogen and oxygen are trapped in the voids around nc-Si at low annealing temperatures. High-temperature annealing during the formation of nc-Si causes hydrogen originally residing in the SiO 2 /substrate region to enter the SiO 2 structure. Hydrogen diffuse back to the SiO 2 /substrate region on annealing in vacuum at 400°C because no other impurities block its diffusion channels. At annealing temperatures above 700°C, both nitrogen and oxygen react with nc-Si, resulting in a volume increase. This introduces stress in the SiO 2 matrix, which is relaxed by the shrinkage of its intrinsic open volume. The present data suggest that nitrogen suppresses Si diffusion in SiO 2 , so that the agglomeration of nc-Si is slower during annealing in nitrogen than in oxygen or vacuum.

show abstract

Section: Discussionmentioning

confidence: 99%

Characterization of the interface region during the agglomeration of silicon nanocrystals in silicon dioxide

Pi¹,

Coleman²,

Harding³

et al. 2004

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The interest in nanosized Si was first sparked by the discovery of room-temperature optical emission in porous Si [1,2], and was subsequently boosted by reports of highly efficient photoluminescence (PL) in Si nanostructures [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Optical emission fromSiO2-embedded silicon nanocrystals: A high-pressure Raman and photoluminescence study

et al. 2015

View full text Add to dashboard Cite

We investigate the optical properties of high-quality Si nanocrystals (NCs)/SiO 2 multilayers under high hydrostatic pressure with Raman scattering and photoluminescence (PL) measurements. The aim of our study is to shed light on the origin of the optical emission of the Si NCs/SiO 2 . The Si NCs were produced by chemical-vapor deposition of Si-rich oxynitride (SRON)/SiO 2 multilayers with 5-and 4-nm SRON layer thicknesses on fused silica substrates and subsequent annealing at 1150°C, which resulted in the precipitation of Si NCs with an average size of 4.1 and 3.3 nm, respectively. From the pressure dependence of the Raman spectra we extract a phonon pressure coefficient of 8.5 ± 0.3 cm −1 /GPa in both samples, notably higher than that of bulk Si (5.1 cm −1 /GPa). This result is ascribed to a strong pressure amplification effect due to the larger compressibility of the SiO 2 matrix. In turn, the PL spectra exhibit two markedly different contributions: a higher-energy band that redshifts with pressure, and a lower-energy band which barely depends on pressure and which can be attributed to defect-related emission. The pressure coefficients of the higher-energy contribution are (−27 ± 6) and (−35 ± 8) meV/GPa for the Si NCs with a size of 4.1 and 3.3 nm, respectively. These values are sizably higher than those of bulk Si (−14 meV/GPa). When the pressure amplification effect observed by Raman scattering is incorporated into the analysis of the PL spectra, it can be concluded that the pressure behavior of the high-energy PL band is consistent with that of the indirect transition of Si and, therefore, with the quantum-confined model for the emission of the Si NCs.

show abstract

“…Thus SiO x is considered to be a practical and promising material for Si-based LEDs. SiO x embedded with Si NCs has been synthesized by several techniques, such as ion implantation of Si + into Si dioxide ͑SiO 2 ͒ films, 5 cosputtering of Si and SiO 2 , 6 evaporation of Si monoxide (SiO), 7 pulsed laser deposition (PLD) of Si in oxygen (O 2 ) gas, 8 and plasmaenhanced chemical vapor deposition (PECVD) of SiO x . 9 The ability to control the size distribution and surface condition of Si NCs with reproducibility is critical due to the sensitive light emitting properties of Si NCs.…”

Section: Introductionmentioning

confidence: 99%

Annealing and oxidation of silicon oxide films prepared by plasma-enhanced chemical vapor deposition

Chen

Tang

et al. 2004

Journal of Applied Physics

111

View full text Add to dashboard Cite

We have investigated phase separation, silicon nanocrystal (Si NC) formation and optical properties of Si oxide (SiO x , 0Ͻ x Ͻ 2) films by high-vacuum annealing and dry oxidation. The SiO x films were deposited by plasma-enhanced chemical vapor deposition at different nitrous-oxide/silane flow ratios. The physical and optical properties of the SiO x films were studied as a result of high-vacuum annealing and thermal oxidation. X-ray photoelectron spectroscopy (XPS) reveals that the as-deposited films have a random-bonding or continuous-random-network structure with different oxidation states. After annealing at temperatures above 1000°C, the intermediate Si continuum in XPS spectra (referring to the suboxide) split to Si peaks corresponding to SiO 2 and elemental Si. This change indicates the phase separation of the SiO x into more stable SiO 2 and Si clusters. Raman, high-resolution transmission electron microscopy and optical absorption confirmed the phase separation and the formation of Si NCs in the films. The size of Si NCs increases with increasing Si concentration in the films and increasing annealing temperature. Two photoluminescence (PL) bands were observed in the films after annealing. The ultraviolet (UV)-range PL with a peak fixed at 370-380 nm is independent of Si concentration and annealing temperature, which is a characteristic of defect states. Strong PL in red range shows redshifts from ϳ600 to 900 nm with increasing Si concentration and annealing temperature, which supports the quantum confinement model. After oxidation of the high-temperature annealed films, the UV PL was almost quenched while the red PL shows continuous blueshifts with increasing oxidation time. The different oxidation behaviors further relate the UV PL to the defect states and the red PL to the recombination of quantum-confined excitions.

show abstract

Blue photoluminescence and local structure of Si nanostructures embedded in SiO2 matrices

Cited by 124 publications

References 0 publications

Characterization of the interface region during the agglomeration of silicon nanocrystals in silicon dioxide

Characterization of the interface region during the agglomeration of silicon nanocrystals in silicon dioxide

Optical emission fromSiO2-embedded silicon nanocrystals: A high-pressure Raman and photoluminescence study

Annealing and oxidation of silicon oxide films prepared by plasma-enhanced chemical vapor deposition

Contact Info

Product

Resources

About