scholarly journals Carrier Storage in Ge Nanocrystals Grown on Silicon Oxide by a Two Step Dewetting / Nucleation Process

Nanocrystals ◽  
10.5772/10092 ◽  
2010 ◽  
Author(s):  
Abdelillah El ◽  
Michel Troyon ◽  
Karim Gacem ◽  
Quang-Tri Do
Keyword(s):  
Silicon Oxide ◽  
Nucleation Process ◽  
Ge Nanocrystals

Phonon confinement in Ge nanocrystals in silicon oxide matrix

2011 ◽  
Vol 109 (3) ◽  
pp. 033107 ◽  
Author(s):  
Yiaxiong Jie ◽  
A. T. S. Wee ◽  
C. H. A. Huan ◽  
Z. X. Shen ◽  
W. K. Choi
Keyword(s):  
Silicon Oxide ◽  
Phonon Confinement ◽  
Oxide Matrix ◽  
Ge Nanocrystals

Raman Shift and Broadening in Stress-Minimized Ge Nanocrystals in Silicon Oxide Matrix

1999 ◽  
Vol 581 ◽  
Author(s):  
YX Jie ◽  
CHA Huan ◽  
ATS Wee ◽  
ZX Shen
Keyword(s):  
Silicon Oxide ◽  
Phonon Dispersion ◽  
Weighting Function ◽  
Rf Magnetron Sputtering ◽  
Raman Shift ◽  
Stress Effect ◽  
Phonon Confinement ◽  
Peak Broadening ◽  
Non Gaussian ◽  
Ge Nanocrystals

ABSTRACTGe nanocrystals (nc-Ge) embedded in silicon oxide films were synthesized using RF magnetron sputtering and post-annealing procedure. To minimize the stress effect and inhomogeneity, we intentionally lower the cooling rates and reduce the temperature gradient during annealing. Significant Raman shifts ranging from 2.0 to 5.8 cm−1 have been observed from samples annealed at different temperatures. The size-dependent shift and broadening is found to be in good agreement with the phonon confinement mode together with the Gaussian weighting function, and the isotropic T02 phonon dispersion relation introduced by Sasaki et al. The Raman spectra can also be well-fitted using peaks calculated from the phonon confinement model. The inhomogeneous Raman peak broadening from our samples annealed at lower temperatures are attributed to the non-Gaussian size distribution of Ge nanocrystals.

Luminescence and X-ray diffraction studies of Ge nanocrystals in amorphous silicon oxide

2000 ◽  
Vol 286 (1) ◽  
pp. 161-164 ◽  
Author(s):  
V Ng ◽  
S.P Ng ◽  
H.H Thio ◽  
W.K Choi ◽  
A.T.S Wee ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Silicon Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Silicon Oxide ◽  
Ge Nanocrystals

Raman and photoluminescence properties of Ge nanocrystals in silicon oxide matrix

2004 ◽  
Vol 107 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Y.X Jie ◽  
A.T.S Wee ◽  
C.H.A Huan ◽  
W.X Sun ◽  
Z.X Shen ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Photoluminescence Properties ◽  
Oxide Matrix ◽  
Ge Nanocrystals

scholarly journals Growth Mechanism and Surface Structure of Ge Nanocrystals Prepared by Thermal Annealing of Cosputtered GeSiO Ternary Precursor

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Bo Zhang ◽  
Yong Xiang ◽  
Santosh Shrestha ◽  
Martin Green ◽  
Gavin Conibeer
Keyword(s):  
Surface Layer ◽  
Thermal Annealing ◽  
Growth Mechanism ◽  
Silicon Oxide ◽  
Volume Fraction ◽  
Growth Models ◽  
Atomic Layer ◽  
Spectroscopic Techniques ◽  
Superlattice Structure ◽  
Ge Nanocrystals

Ge nanocrystals (Ge-ncs) embedded in a SiO2superlattice structure were prepared by magnetron cosputtering and postdeposition annealing. The formation of spherical nanocrystals was confirmed by transmission electron microscopy and their growth process was studied by a combination of spectroscopic techniques. The crystallinity volume fraction of Ge component was found to increase with crystallite size, but its overall low values indicated a coexistence of crystalline and noncrystalline phases. A reduction of Ge-O species was observed in the superlattice during thermal annealing, accompanied by a transition from oxygen-deficient silicon oxide to silicon dioxide. A growth mechanism involving phase separation of Ge suboxides (GeOx) was then proposed to explain these findings and supplement the existing growth models for Ge-ncs in SiO2films. Further analysis of the bonding structure of Ge atoms suggested that Ge-ncs are likely to have a core-shell structure with an amorphous-like surface layer, which is composed of GeSiO ternary complex. The surface layer thickness was extracted to be a few angstroms and equivalent to several atomic layer thicknesses.

Comparison of the Synthesis of Ge Nanocrystals in Hafnium Aluminum Oxide and Silicon Oxide Matrices

2009 ◽  
Vol 9 (2) ◽  
pp. 1577-1581 ◽  
Author(s):  
H. G. Chew ◽  
F. Zheng ◽  
W. K. Choi ◽  
W. K. Chim ◽  
E. A. Fitzgerald ◽  
...  
Keyword(s):  
Aluminum Oxide ◽  
Silicon Oxide ◽  
Ge Nanocrystals

scholarly journals Highly Improved Mis Photodetector Sensitivity Using Ge Nanocrystals

2021 ◽  
Author(s):  
Mansour Aouassa ◽  
Ridha M’gaieth ◽  
Bilel Azeza ◽  
Isabelle Berbezier ◽  
Luc Favre
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
High Performance ◽  
Silicon Oxide ◽  
High Sensitivity ◽  
Cmos Technology ◽  
Photocurrent Generation ◽  
Photocurrent Spectroscopy ◽  
Transmission Electron ◽  
Ge Nanocrystals

Abstract We report the high performances of Metal-Insulator-Semiconductor Photodetectors (MIS PD) made with crystalline Ge nanocrystals (Ge NCs) as the active absorbers embedded in a silicon dioxide matrix. The Ge NCs have been obtained by a combination of Ge deposition by Molecular Beam Epitaxy (MBE) on tunnel thermal silicon oxide and solid state dewetting processes. Ge NCs structure and morphology are characterized by High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Electron Microscopy (SEM). The photocurrent generation is determined by I-V spectroscopy and Photocurrent spectroscopy. We evidence the role of high quality Ge NCs on photocurrent and explain the high sensitivity of MIS photodetector as a result of transport mechanisms via photoexcited Ge NCs.These results indicate that the crystalline Ge NCs obtained via solid state dewetting can be integrated with opto-electronics and photonics technologies to produce new high performance optoelectronic devices fully compatible with Complementary Oxide Metal (CMOS) technology.

Analytical Electron Microscopy Study of Second-Phase Particles in 7075 and 7475 Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 348-349
Author(s):  
M. Raghavan ◽  
J. Y. Koo ◽  
J. W. Steeds ◽  
B. K. Park
Keyword(s):  
Aluminum Alloys ◽  
Silicon Oxide ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Partial Substitution ◽  
Second Phase ◽  
X Ray ◽  
Second Phase Particles ◽  
Almost All

X-ray microanalysis and Convergent Beam Electron Diffraction (CBD) studies were conducted to characterize the second phase particles in two commercial aluminum alloys -- 7075 and 7475. The second phase particles studied were large (approximately 2-5μm) constituent phases and relatively fine ( ∼ 0.05-1μn) dispersoid particles, Figures 1A and B. Based on the crystal structure and chemical composition analyses, the constituent phases found in these alloys were identified to be Al7Cu2Fe, (Al,Cu)6(Fe,Cu), α-Al12Fe3Si, Mg2Si, amorphous silicon oxide and the modified 6Fe compounds, in decreasing order of abundance. The results of quantitative X-ray microanalysis of all the constituent phases are listed in Table I. The data show that, in almost all the phases, partial substitution of alloying elements occurred resulting in small deviations from the published stoichiometric compositions of the binary and ternary compounds.

LVSEM: Past Present and Future

1990 ◽  
Vol 48 (1) ◽  
pp. 364-365
Author(s):  
James B. Pawley
Keyword(s):  
Field Emission ◽  
Line Width ◽  
Time Scales ◽  
Silicon Oxide ◽  
Beam Current ◽  
High Brightness ◽  
High Beam ◽  
Fixed Charges ◽  
Beam Voltage ◽  
Deposited Metal

Past: In 1960 Thornley published the first description of SEM studies carried out at low beam voltage (LVSEM, 1-5 kV). The aim was to reduce charging on insulators but increased contrast and difficulties with low beam current and frozen biological specimens were also noted. These disadvantages prevented widespread use of LVSEM except by a few enthusiasts such as Boyde. An exception was its use in connection with studies in which biological specimens were dissected in the SEM as this process destroyed the conducting films and produced charging unless LVSEM was used.In the 1980’s field emission (FE) SEM’s came into more common use. The high brightness and smaller energy spread characteristic of the FE-SEM’s greatly reduced the practical resolution penalty associated with LVSEM and the number of investigators taking advantage of the technique rapidly expanded; led by those studying semiconductors. In semiconductor research, the SEM is used to measure the line-width of the deposited metal conductors and of the features of the photo-resist used to form them. In addition, the SEM is used to measure the surface potentials of operating circuits with sub-micrometer resolution and on pico-second time scales. Because high beam voltages destroy semiconductors by injecting fixed charges into silicon oxide insulators, these studies must be performed using LVSEM where the beam does not penetrate so far.

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