Patterned Structures of Silicon Nanocrystals Prepared by Pulsed Laser Interference Crystallization of Ultra-Thin A-Si:H Single-Layer

2002 ◽  
Vol 737 ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Qiao ◽  
Leyi Zhu ◽  
Wei Li ◽  
Jian Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystalline Silicon ◽  
Pulsed Laser ◽  
Single Layer ◽  
Laser Interference ◽  
Raman Scattering Spectroscopy ◽  
Transmission Electron ◽  
Patterned Structures ◽  
Device Applications ◽  
Si Films

ABSTRACTWe employ the method of phase-modulated KrF excimer pulsed laser interference crystallization to fabricate nanometer-sized crystalline silicon (nc-Si) with the two-dimensional (2D) patterned distribution within the ultra-thin a-Si:H single-layer. The local crystallization occurs after interference laser irradiation under proper energy density. The results of atomic force microscopy, Raman scattering spectroscopy, cross-section transmission electron microscopy and scanning electron microscopy demonstrate that Si nano-crystallites are formed within the initial a-Si:H single-layer, selectively located in the discal regions with the diameter of 350 nm and patterned with the same 2D periodicity of 2.0 μm as the phase-shifting grating. The results show that the present method can be used to fabricate patterned nc-Si films for device applications.

TWO-DIMENSIONAL PATTERNED NANOCRYSTALLINE Si ARRAY PREPARED BY LASER INTERFERENCE CRYSTALLIZATION OF ULTRA-THIN AMORPHOUS Si:H SINGLE-LAYER

2002 ◽  
Vol 01 (05n06) ◽  
pp. 603-609
Author(s):  
XINFAN HUANG ◽  
XIAOWEI WANG ◽  
FENG QIAO ◽  
LEYI ZHU ◽  
WEI LI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystalline Silicon ◽  
Single Layer ◽  
Two Dimensional ◽  
Laser Interference ◽  
Raman Scattering Spectroscopy ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Device Applications ◽  
Si Films

We employ the method of phase-modulated KrF excimer pulsed laser interference crystallization to fabricate nanometer-sized crystalline silicon with two-dimensional patterned distribution within the ultra-thin amouphous Si:H single-layer. The local phase transition occurs in ultra-thin a-Si:H film after laser interference crystallization under proper energy density. The results of atomic force microscopy, Raman scattering spectroscopy, cross-section transmission electron microscopy and scanning electron microscopy demonstrate that Si nanocrystallites are formed within the initial a-Si:H single-layer, selectively located in the discal regions with the diameter of 250 nm and patterned with the same 2D periodicity of 2.0 μm as the phase-shifting grating. The results demonstrate that the present method can be used to fabricate patterned nc-Si films for device applications.

Microstructural Evolution of Nickel Induced Crystallization of Amorphous Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
Kyu Ho Park ◽  
Young Woo Jeong ◽  
Hyun Ja Kwon ◽  
Jeong Soo Lee ◽  
Binn Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Amorphous Silicon ◽  
Microstructural Evolution ◽  
Crystalline Silicon ◽  
Transmission Electron ◽  
Si Films ◽  
Induced Crystallization

AbstractThe Ni silicide-mediated phase transformation of amorphous to crystalline silicon (c-Si) was studied using transmission electron microscopy. Amorphous silicon (a-Si) films coated with very thin Ni layer (∼10-1Å) were annealed at various temperatures. Randomly oriented NiSi2 precipitates were observed in the Ni deposited a-Si film annealed at 400°C. The nucleation of the epitaxial c-Si has occurred on the {111} faces of the octahedral NiSi2 precipitate at 430°C and then caused to the variation in the shape of the NiSi2 precipitates. During the growth of c-Si, the needle-like morphology developed from the migration of NiSi2 precipitates through the a-Si matrix leaving a trail of c-Si. The collision of a migrating NiSi2 precipitate with a stationary NiSi2 precipitates in the a-Si film gave rise to the change in the morphology of the growing Si grain and the formation of additional c-Si needles on variants of the <111> direction.

Laser assisted synthesis of WS2 nanorods by pulsed laser ablation in liquid environment

2021 ◽  
pp. 2140007
Author(s):  
Pankaj Koinkar ◽  
Kohei Sasaki ◽  
Tetsuro Katayama ◽  
Akihiro Furube ◽  
Satoshi Sugano
Keyword(s):  
Electron Microscopy ◽  
Laser Ablation ◽  
2D Materials ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Ablation In Liquid ◽  
Simple Method ◽  
Liquid Environment ◽  
Transmission Electron ◽  
Specific Morphology

Two dimensional (2D) materials are widely attracting the interest of researchers due to their unique crystal structure and diverse properties. In the present work, tungsten disulfide (WS[Formula: see text] nanorods were synthesized by a simple method of pulsed laser ablation in liquid (PLAL) environment. The prepared WS2 are analyzed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis) and Raman spectroscopy to confirm the surface morphology, phase and structure. A possible growth mechanism of WS2 is proposed. This study indicates new door for the preparation of 2D materials with specific morphology.

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

Atomic Structure and Property Correlation in Pulsed Laser Deposited High -Tc Films

1998 ◽  
Vol 526 ◽  
Author(s):  
R. Kalyanaraman ◽  
S. Oktyabrsky ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Structure And Property ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Z Contrast

AbstractThe atomic structure of grain boundaries in pulsed laser deposited YBCO/MgO thin films have been studied using transmission electron microscopy. The films have perfect texturing with YBCO(001)//MgO(001), giving rise to low-angle [001] tilt boundaries from the grains with the c-axis normal to substrate surface. Low angle grain boundaries have been found to be aligned preferentially along (100) and (110) interface planes. The energy of (110) boundary planes described by an alternating array of [100] and [010] dislocation is found to be comparable to the energy of a (100) boundary. The existence of these split dislocations is shown to further reduce the theoretical current densities of these boundaries indicating that (110) boundaries carry less current as compared to (100) boundaries of the same misorientation angle. Further, Z-contrast transmission electron microscopy of a 42° asymmetric high-angle grain boundary of YBCO shows evidence for the existence of boundary fragments and a reduced atomic density along the boundary plane

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.

Nano-Thermometry: Transmission Electron Microscopy of Femtosecond Laser Irradiated Co/Si Multilayer Thin Foils

2005 ◽  
Vol 899 ◽  
Author(s):  
Yoosuf Picard ◽  
Steven M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Silicon ◽  
Heat Dissipation ◽  
Crystalline Silicon ◽  
Pulse Length ◽  
Multilayer Systems ◽  
Hole Edge ◽  
Thin Foils ◽  
Transmission Electron

AbstractPre-thinned foils composed of amorphous silicon and polycrystalline cobalt were irradiated using femtosecond pulse-length lasers at fluences sufficient for ablation (material removal). The resultant ablated hole and surrounding vicinity was studied using transmission electron microscopy to determine modifications to the structure. Evidence of cobalt silicide formation was observed within a 3 micron radius of the laser hole edge by use of selected area electron diffraction (SAED). In addition, elongated grains of crystalline silicon was observed within 500 nm of the laser hole edge, indicating melting of the amorphous silicon and heat dissipation slow enough to allow recyrstallization. This initial work demonstrates the use of pre-designed nanostructured multilayer systems as a method for nanoscale profiling of heat dissipation following pulsed laser irradiation.

Determination of the Distribution of Ion Implantation Boron in Silicon

2000 ◽  
Vol 650 ◽  
Author(s):  
Te-Sheng Wang ◽  
A.G. Cullis ◽  
E.J.H. Collart ◽  
A.J. Murrell ◽  
M.A. Foad
Keyword(s):  
Electron Microscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Low Energy ◽  
Concentration Profiles ◽  
Impurity Profile ◽  
Transmission Electron ◽  
Device Applications ◽  
P Type ◽  
Secondary Ion

ABSTRACTBoron is the most important p-type dopant in Si and it is essential that, especially for low energy implantation, both as-implanted B distributions and those produced by annealing should be characterized in very great detail to obtain the required process control for advanced device applications. While secondary ion mass spectrometry (SIMS) is ordinarily employed for this purpose, in the present studies implant concentration profiles have been determined by direct B imaging with approximately nanometer depth and lateral resolution using energy-filtered imaging in the transmission electron microscopy. The as-implanted B impurity profile is correlated with theoretical expectations: differences with respect to the results of SIMS measurements are discussed. Changes in the B distribution and clustering that occur after annealing of the implanted layers are also described.

Surface Disorder and Exfoliation in Lithographically Textured Molybdenum Disulfide

1986 ◽  
Vol 82 ◽  
Author(s):  
C. B. Roxlo ◽  
H. W. Deckman ◽  
J. H. Dunsmuir ◽  
A. F. Ruppert ◽  
R. R. Chianelli
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molybdenum Disulfide ◽  
Layered Structure ◽  
Single Layer ◽  
Chemical Treatments ◽  
Transmission Electron ◽  
Surface Disorder ◽  
Edge Surface

ABSTRACTLithographic techniques have been used to prepare transmission electron microscopy samples of MoS2, allowing examination of the edge surface with single-layer resolution. We observe that these surfaces are easily disordered by chemical treatments common in the catalysis industry. In some cases treatment in H2/H2S leads to an exfoliation of the layered structure, a process which can be observed as it occurs in the microscope.

Encapsulated Fullerenes Within Single Wall Carbon Nanotubes

1999 ◽  
Vol 5 (S2) ◽  
pp. 182-183
Author(s):  
Brian W. Smith ◽  
David E. Luzzi
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Pulsed Laser ◽  
Irradiation Damage ◽  
Laser Vaporization ◽  
Single Wall Carbon Nanotubes ◽  
Phase Object ◽  
Parallel Lines ◽  
Weak Phase ◽  
Transmission Electron

It is well documented that the pulsed laser vaporization of graphite produces both carbon nanotubes and C60 in the presence of certain metallic catalysts. In nanotube production most of the Ceo is removed along with other residual contaminants during succeeding purification and annealing steps. The possibility of C60 becoming trapped inside a nanotube during this elaborate sequence has been considered but not previously detected.Nanotubes are observed with high resolution transmission electron microscopy under conditions chosen to minimize both exposure time and irradiation damage. Since a nanotube satisfies the weak phase object approximation, its image is a projection of the specimen -potential in the direction of the electron beam. The image has maximum contrast where the beam encounters the most carbon atoms, which occurs where it is tangent to the tube’s walls. Thus, the image consists of two dark parallel lines whose separation is equal to the tube diameter, 1.4 nm.

Sign in / Sign up

Export Citation Format

Share Document