Optical properties of porous silicon

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1184-1193 ◽  
Author(s):  
D. J. Lockwood ◽  
G. C. Aers ◽  
L. B. Allard ◽  
B. Bryskiewicz ◽  
S. Charbonneau ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Confinement ◽  
Chemical Dissolution ◽  
Optical Absorption Spectra ◽  
Porous Si ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Nanostructures ◽  
Si Films

The optical and structural properties of porous Si films produced by electrochemical and chemical dissolution of Si have been studied by a variety of techniques. Raman scattering and transmission electron microscopy have shown the samples to contain crystalline Si wires and (or) spherites 3–8 nm in diameter and (or) amorphous Si. The optical absorption spectra and the wavelength, temperature, and lifetime dependence of the photoluminescence obtained from most of the samples are entirely consistent with the quantum confinement of excitons in Si nanostructures. Quite different photoluminescence was obtained from other samples composed only of amorphous Si, and this is attributed to the presence of silicon oxyhydride species.

Light Emission from Porous Silicon Subjected to Rapid Thermal Oxidation

1992 ◽  
Vol 283 ◽  
Author(s):  
A. G. Cullis ◽  
L. T. Canham ◽  
G. M. Williams ◽  
P. W. Smith ◽  
O. D. Dosser
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Porous Silicon ◽  
Light Emission ◽  
Porous Si ◽  
Light Emitting ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron ◽  
Si Nanostructures

ABSTRACTLuminescent oxidised porous Si is produced by rapid thermal annealing of the anodised material in a dry oxygen ambient. Its light-emitting properties are studied by both photoluminescence and cathodoluminescence methods. The structure of the oxidised material is examined by transmission electron microscopy, while its oxygen content is determined by X-ray microanalysis. These investigations show that crystalline Si nanostructures remain in the oxidised porous material and account for its luminescence properties. The work demonstrates that the speculated importance of either Si-based amorphous phases or the interesting material, siloxene, in this regard is unrealistic.

Lateral Solid Phase Epitaxy of Evaporated Amorphous Si Films onto SiO2 Patterns

1983 ◽  
Vol 25 ◽  
Author(s):  
H. Yamamoto ◽  
H. Ishiwara ◽  
S. Furukawa ◽  
M. Tamura ◽  
T. Tokuyama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Si Substrates ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films ◽  
Kinetics Of

ABSTRACTLateral solid phase epitaxy (L-SPE) of amorphous Si (a-Si) films vacuum-evaporated on Si substrates with SiO2 patterns has been investigated, in which the film first grows vertically in the regions directly contacted to the Si substrates and then grows laterally onto SiO2 patterns. It has been found from transmission electron microscopy and Nomarski optical microscopy that use of dense a-Si films, which are formed by evaporation on heated substrates and subsequent amorphization by Si+ ion implantation, is essentially important for L-SPE. The maximum L-SPE length of 5–6μm was obtained along the <010> direction after 10hourannealing at 600°C. The kinetics of the L-SPE growth has also been investigated.

Structural Investigation of Photoluminescent Porous Si by Transmission Electron Microscopy

1992 ◽  
Vol 281 ◽  
Author(s):  
S. Shih ◽  
K. H. Jung ◽  
D. L. Kwong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Structural Investigation ◽  
Amorphous Material ◽  
Porous Si ◽  
Plan View ◽  
Mesh Structure ◽  
Transmission Electron ◽  
Minimal Damage

ABSTRACTWe have developed a new, minimal damage approach for examination of luminescent porous Si layers (PSLs) by transmission electron microscopy (TEM). In this approach, chemically etched PSLs are fabricated after conventional plan-view TEM sample preparation. A diffraction pattern consisting of a diffuse center spot, characteristic of amorphous material, is primarily observed. However, crystalline, microcrystalline, and amorphous regions could all be observed in selected areas. A crystalline mesh structure could be observed in some of the thin areas near the pinhole. The microcrystallite sizes were 15–150 Å and decreased in size when located further from the pinhole.

Structural Properties of Amorphous Silicon Produced by Electron Irradiation

1999 ◽  
Vol 557 ◽  
Author(s):  
J. Yamasaki ◽  
S. Takeda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Distribution Function ◽  
Structural Properties ◽  
Electron Irradiation ◽  
Low Temperatures ◽  
Crystalline Silicon ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Means Of Transmission

AbstractThe structural properties of the amorphous Si (a-Si), which was created from crystalline silicon by 2 MeV electron irradiation at low temperatures about 25 K, are examined in detail by means of transmission electron microscopy and transmission electron diffraction. The peak positions in the radial distribution function (RDF) of the a-Si correspond well to those of a-Si fabricated by other techniques. The electron-irradiation-induced a-Si returns to crystalline Si after annealing at 550°C.

Crystallization of Amorphous Si In Al/Si Multilayers

1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Layered Structure ◽  
Heat Of Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Amorphous Si

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.

Deformation of Monocrystalline Silicon under Nanoscratching

2008 ◽  
Vol 41-42 ◽  
pp. 15-19 ◽  
Author(s):  
Y.Q. Wu ◽  
Han Huang ◽  
Jin Zou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Applied Load ◽  
Normal Load ◽  
Stacking Faults ◽  
Monocrystalline Silicon ◽  
Crystalline Region ◽  
Density Of Dislocations ◽  
Transmission Electron ◽  
Amorphous Si

In this work, deformation of monocrystalline silicon (Si) under nanoscratching was investigated using transmission electron microscopy (TEM). The results indicated that no fracture occurred during nanoscratching with loads ranging from 1 to 6 mN. The damaged regions induced by nanoscratching included an amorphous Si region and a damaged crystalline Si region. Detailed TEM analyses revealed that at the lowest load of 1 mN no dislocation was observed in the damaged crystalline region, and only stacking faults were observed at the boundary between the damaged crystalline Si and amorphous Si. Dislocations started to nucleate along (111) planes and penetrated into the bulk Si when the normal load was increased to 2 mN and above. Defects perpendicular to the scratched surface were initiated when the load was greater than 4 mN. The density of dislocations also increased rapidly with the increase of the applied load.

The Study on Surface Chemistry of Nanoporous Black Si Layers

2011 ◽  
Vol 79 ◽  
pp. 304-308
Author(s):  
Wang Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Chemistry ◽  
Point Defects ◽  
High Density ◽  
Nanometer Scale ◽  
Transmission Electron ◽  
One Step ◽  
Amorphous Si ◽  
Microscopy Techniques

We reported our detailed investigation of the microstructure and surface chemistry of nanoporous black Si layers using transmission electron microscopy techniques such as HRTEM, EDS, and EELS. We found that a one-step nanoparticle-catalyzed liquid etch creates deep conical nanovoids. The cones provide the density-graded surface that suppresses reflection. The surface of the as-etched nanoporous black Si is an amorphous Si suboxide (SiOx) produced by the strongly oxidizing nanocatalyzed etch. The c-Si/suboxide interface is rough at the nanometer scale and contains a high density of point defects.

Wet Oxidation of Si1-x-yGexCy Layers on (100) Si

1995 ◽  
Vol 398 ◽  
Author(s):  
A. E. Bair ◽  
Z. Atzmon ◽  
T. L. Alford ◽  
D. Chandrasekhar ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Oxidation Behavior ◽  
Rutherford Backscattering Spectrometry ◽  
Reference Sample ◽  
Oxide Growth ◽  
Wet Oxidation ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Content Alloy

ABSTRACTSingle crystal Si0.63Ge0.36C0.01 and amorphous Si0.65Ge0.27C0.08 layers have been oxidized in a wet ambient at 700 °C and 900 °C. The oxide growth has been studied using Rutherford backscattering spectrometry and transmission electron microscopy. A reference sample of Si0.63Ge0.37 was also oxidized in order to determine the influence of C on the oxidation behavior. The lower C content alloy behaved similar to the SiGe alloy. Uniform Si1-xGexO2 was obtained at 700 °C whereas SiO2 was formed at 900 °C, and Ge piled up underneath the oxide. In both cases, C was not detected in the oxide layer. The amorphous Si0.65Ge0.27C0.08 alloy behaved significantly different at both oxidation temperatures in comparison with the crystalline Si0.63Ge0.36C0.01 and Si0.63Ge0.37. Negligible oxidation occurred at 700 °C whereas SiO2 was obtained at 900 °C and the rejected Ge distributed uniformly throughout the SiGeC alloy. It is proposed that fast Ge diffusion during oxidation at 900 °C resulted from diffusion at grain boundaries, since crystallization of the amorphous SiGeC layer occurred in conjunction with oxidation, leading to nucleation of ∼5 nm nanocrystals.

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