Quantum size effects on photoluminescence in ultrafine Si particles

Takagi, H.; Ogawa, Hisahito; Yamazaki, Y.; Ishizaki, A.; Nakagiri, T.

doi:10.1063/1.102921

Cited by 883 publications

(346 citation statements)

References 6 publications

Supporting

Mentioning

317

Contrasting

Unclassified

Order By: Relevance

“…However, Si-(nc) peaks are known to enhance in magnitude and shift toward red due to their increased size. [1][2][3][4] Moreover, defect related PL is generally observed between 350 and 600 nm and does not red shift with annealing. On the basis of the observed enhancement and red shift of the PL with increasing annealing time and temperature, we conclude that our samples contain silicon nanocrystals.…”

Section: Methodsmentioning

confidence: 96%

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix

et al. 2005

View full text Add to dashboard Cite

We investigated silicon nanoclusters Si(nc) in a SiO 2 matrix prepared by the plasma-enhanced chemical vapor deposition technique, using X-ray photoelectron spectroscopy (XPS) with external voltage stimuli in both static and pulsed modes. This method enables us to induce an additional charging shift of 0.8 eV between the Si2p peaks of the oxide and the underlying silicon, both in static and time-resolved modes, for a silicon sample containing a 6 nm oxide layer. In the case of the sample containing silicon nanoclusters, both Si2p peaks of Si(nc) and host SiO 2 undergo a charging shift that is 1 order of magnitude larger (>15 eV), with no measurable difference between them (i.e., no differential charging between the silicon nanoclusters and the oxide matrix could be detected). By use of a measured Auger parameter, we estimate the relaxation energy of the Si(nc) in the SiO 2 matrix as -0.4 eV, which yields a -0.6 eV shift in the binding energy of the Si(nc) with respect to that of bulk Si in the opposite direction of the expected quantum size effect. This must be related to the residual differential charging between the silicon nanoclusters and the oxide host. Therefore, differential charging is still the biggest obstacle for extracting size-dependent binding energy shifts with XPS when one uses the oxide peak as the reference.

show abstract

Section: Methodsmentioning

confidence: 96%

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix

et al. 2005

View full text Add to dashboard Cite

show abstract

“…In photoluminescence ͑PL͒ increased efficiency of excitonic emission and its gradual shift to higher energies upon size reduction have been experimentally observed. 4,5 Light emission with the energy exceeding the band gap of bulk silicon has been reported in nanocrystals of a few-nanometers size. Any experiment conducted on few-nanometer silicon grains is sensitive to surface effects in an unpredictable way.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of band structure modification in silicon nanocrystals

et al. 2001

View full text Add to dashboard Cite

Experimental studies of size-related effects in silicon nanocrystals are reported. We present investigations carried out on nanocrystals prepared from single-crystal Si:P wafer by ball milling. The average final grain dimension varied depending on the way of preparation in the range between 70 and 230 nm. The ball milling was followed by sedimentation and selection of the smallest grains. The initial grain size distribution was measured by scanning electron microscopy. Further reduction in size was achieved by oxidation at 1000°C which creates a silicon dioxide layer around a silicon core. The oxidation process was monitored by transmission electron microscopy and the growth speed of SiO 2 was estimated in order to model the grain size of nanocrystals. Crystallinity of silicon grains was confirmed by x-ray diffraction and by transmission electron microscopy using a bright/dark field method and selected area diffraction pattern. In the silicon nanocrystals the electron energy levels are shifted which was observed separately for conduction band, valence band and energy band gap. Electron paramagnetic resonance was applied to investigate variation of the conduction band minimum by monitoring its influence on the hyperfine interaction of phosphorus shallow donor. On the basis of these results an explicit expression for conduction band upshift as a function of average grain size has been derived. Information about the downshift of the valence band was obtained from measurements on a photoluminescence band related to a deep to shallow level transition. A perturbation of a few meV for grain sizes of the order about 100 nm has been observed. Internal consistency of these findings has been examined by investigation of the photoluminescence band due to an electron-hole recombination whose energy is directly related to the band gap of silicon.

show abstract

“…Since small particles of silicon of 20-30 Å diameter have been observed to have crystalline bulklike lattices, 14,15 obtaining information about the structures of small clusters and the transition to bulklike crystalline or amorphous structure would be extremely important in the study of basic material properties and growth processes.…”

Section: Introductionmentioning

confidence: 99%

Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy

Honea

Ogura

Peale³

et al. 1999

The Journal of Chemical Physics

View full text Add to dashboard Cite

The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton ͑SPP͒ enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N 2 on a liquid He cooled substrate. Raman spectra from monodisperse samples of the smaller clusters studied, Si 4 , Si 6 and Si 7 , show sharp, well-resolved, vibrations which are in good agreement with predictions based on ab initio calculations. From these comparisons we confirm that Si 4 is a planar rhombus, and assign Si 6 as a distorted octahedron and Si 7 as a pentagonal bypyramid. Si 5 depositions down to 5 eV did not reveal a measurable Raman spectrum under our experimental conditions. Evidence for cluster-cluster aggregation ͑or fragmentation͒ was observed under some conditions, even for a ''magic number'' cluster such as Si 6 . The spectra of the aggregated small clusters were identical to those observed for directly deposited larger cluster ''bands,'' such as Si [25][26][27][28][29][30][31][32][33][34][35] . The Raman spectra of the aggregated clusters bear some similarity to those of bulk amorphous silicon. Cluster-deposited thin films were prepared by sublimating the matrix material. Even under these ''soft landing'' conditions, changes in the Raman spectrum are observed with the thin films showing even greater similarity to amorphous silicon.

show abstract

Quantum size effects on photoluminescence in ultrafine Si particles

Cited by 883 publications

References 6 publications

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix

Experimental investigation of band structure modification in silicon nanocrystals

Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy

Contact Info

Product

Resources

About

Quantum size effects on photoluminescence in ultrafine Si particles

Cited by 883 publications

References 6 publications

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO2 Matrix

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO2 Matrix

Experimental investigation of band structure modification in silicon nanocrystals

Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy

Contact Info

Product

Resources

About

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix

X-ray Photoelectron Spectroscopic Analysis of Si Nanoclusters in SiO₂ Matrix