Applying an improved phonon confinement model to the analysis of Raman spectra of germanium nanocrystals

Володин, В. А.; Marin, D. V.; Sachkov, V. A.; Gorokhov, E. B.; Rinnert, H.; Vergnat, M.

doi:10.1134/s1063776114010208

Cited by 73 publications

(39 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The Raman spectrum of the hollow Ge NPs is shown in Figure B as a broad, asymmetric phonon mode centered at ∼278 cm –1 . This result is in agreement with our XRD results showing a featureless diffraction pattern and the literature value of amorphous Ge, which describes a broad band with a maximum between 275 and 280 cm –1 . Several factors such as excitation power, bond strain, and Fano interference may influence the Raman spectra, in particular those of nanomaterials. − Ou et al .…”

Section: Resultssupporting

confidence: 92%

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition

et al. 2016

View full text Add to dashboard Cite

Herein we report the electroless deposition of Ge onto sacrificial Ag nanoparticle (NP) templates to form hollow Ge NPs. The formation of AgI is a necessary component for this reaction. Through a systematic study of surface passivating ligands, we determined that tri-n-octylphosphine is necessary to facilitate the formation of hollow Ge NPs by acting as a transport agent for GeI2 and the oxidized Ag(+) cation (i.e., AgI product). Annular dark-field (ADF) scanning transmission electron microscopy (STEM) imaging of incomplete reactions revealed Ag/Ge core/shell NPs; in contrast, completed reactions displayed hollow Ge NPs with pinholes which is consistent with the known method for dissolution of the nanotemplate. Characterization of the hollow Ge NPs was performed by transmission electron microscopy, ADF-STEM, energy-dispersive X-ray spectroscopy, UV-vis spectrophotometry, and Raman spectroscopy. The galvanic replacement reaction of Ag with GeI2 offers a versatile method for controlling the structure of Ge nanomaterials.

show abstract

Section: Resultssupporting

confidence: 92%

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The Raman peak at 289.5 cm −1 is associated with GeGe bonds in undoped Ge NCs. Compared with the Raman peak at ≈297 cm −1 for GeGe bonds in bulk Ge, the redshift of the current Raman peak at 289.5 cm −1 results from the so‐called phonon confinement effect . It is interesting that the Raman peak associated with GeGe bonds in Ge NCs blueshifts as the doping level of P in Ge NCs increases.…”

Section: Resultsmentioning

confidence: 79%

Structures, Oxidation, and Charge Transport of Phosphorus‐Doped Germanium Nanocrystals

Gao

Wang

et al. 2016

Part & Part Syst Charact

View full text Add to dashboard Cite

The doping of semiconductor nanocrystals (NCs) is crucial for the optimization of the performance of devices based on them. In contrast to recent progress on the doping of compound semiconductor NCs and silicon NCs, the doping of germanium (Ge) NCs has lagged behind. Here it is shown that Ge NCs can be doped with phosphorus (P) during synthesis by a nonthermal plasma. It is found that there are more P atoms in the NC near‐surface region than in the NC core. P doping modifies the surface state of Ge NCs. Compressive strain can be incuced in Ge NCs by P which can explain the P‐doping‐enhanced oxidation resistance of Ge NCs. Stable dispersions of P‐doped Ge NCs in acetonitrile can be cast to produce films for field‐effect transistors (FETs). FET analysis shows that the electrical conductivity and electron mobility of a Ge‐NC film increase with the increase of the P doping level, although the electrical activation efficiency of P in the Ge‐NC film is low. Finally, atomic layer deposition of aluminum oxide at the surface of P‐doped Ge NCs is shown to improve the performance of the FETs.

show abstract

“…The Ge-Ge vibration band is observed at 301.6 cm À1 , which is close to its known position for unstrained Ge ($301.3 cm À1 ). 21,22 Significant changes in the Raman spectra were observed after the sample annealing at 850 C. In particular, the intensity of the Ge-Si vibration mode located between 350 cm À1 and 450 cm À1 strongly increases for both the continuous and the porous film areas (spectra 2 and 3 in Fig. 3).…”

Section: Raman Spectroscopy Characterizationmentioning

confidence: 97%

Raman and photoluminescence spectroscopy of SiGe layer evolution on Si(100) induced by dewetting

Shklyaev

Володин

Stoffel

et al. 2018

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

High temperature annealing of thick (40-100 nm) Ge layers deposited on Si(100) at $400 C leads to the formation of continuous films prior to their transformation into porous-like films due to dewetting. The evolution of Si-Ge composition, lattice strain, and surface morphology caused by dewetting is analyzed using scanning electron microscopy, Raman, and photoluminescence (PL) spectroscopies. The Raman data reveal that the transformation from the continuous to porous film proceeds through strong Si-Ge interdiffusion, reducing the Ge content from 60% to about 20%, and changing the stress from compressive to tensile. We expect that Ge atoms migrate into the Si substrate occupying interstitial sites and providing thereby the compensation of the lattice mismatch. Annealing generates only one type of radiative recombination centers in SiGe resulting in a PL peak located at about 0.7 and 0.8 eV for continuous and porous film areas, respectively. Since annealing leads to the propagation of threading dislocations through the SiGe/Si interface, we can tentatively associate the observed PL peak to the well-known dislocation-related D1 band.

show abstract

Applying an improved phonon confinement model to the analysis of Raman spectra of germanium nanocrystals

Cited by 73 publications

References 24 publications

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition

Structures, Oxidation, and Charge Transport of Phosphorus‐Doped Germanium Nanocrystals

Raman and photoluminescence spectroscopy of SiGe layer evolution on Si(100) induced by dewetting

Contact Info

Product

Resources

About

Applying an improved phonon confinement model to the analysis of Raman spectra of germanium nanocrystals

Cited by 73 publications

References 24 publications

Sacrificial Silver Nanoparticles: Reducing GeI2 To Form Hollow Germanium Nanoparticles by Electroless Deposition

Sacrificial Silver Nanoparticles: Reducing GeI2 To Form Hollow Germanium Nanoparticles by Electroless Deposition

Structures, Oxidation, and Charge Transport of Phosphorus‐Doped Germanium Nanocrystals

Raman and photoluminescence spectroscopy of SiGe layer evolution on Si(100) induced by dewetting

Contact Info

Product

Resources

About

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition

Sacrificial Silver Nanoparticles: Reducing GeI₂ To Form Hollow Germanium Nanoparticles by Electroless Deposition