FABRICATION OF Si NANOCOLUMNS AND Si SQUARE SPIRALS ON SELF-ASSEMBLED MONOLAYER COLLOID SUBSTRATES

2002 ◽  
Vol 01 (01) ◽  
pp. 87-97 ◽  
Author(s):  
Y.-P. ZHAO ◽  
D.-X. YE ◽  
PEI-I WANG ◽  
G.-C. WANG ◽  
T.-M. LU
Keyword(s):  
Electron Microscopy ◽  
Incident Angle ◽  
Cost Effective ◽  
Glancing Angle Deposition ◽  
Deposition Flux ◽  
Self Assembled Monolayer ◽  
Si Substrates ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Angle Deposition

Amorphous silicon nanocolumns, square nanospirals, and multilayer spiral/column rods are fabricated on bare Si substrates and monolayer colloid substrates by glancing angle deposition. The grown films are studied by scanning electron microscopy and transmission electron microscopy. The size of the deposited Si columns and spirals increases with the size of colloid particles for fixed incident angle of deposition flux. The feasibility of fabricating separated, well-ordered square spirals provides a cost effective and simple way to fabricate photonic crystals.

Optimization of Ultra-High Aspect Ratio Nanostructures Fabricated Using Glancing Angle Deposition

2021 ◽  
Author(s):  
Chuang Qu ◽  
Bruce Alphenaar ◽  
Shamus McNamara ◽  
Kevin Walsh
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Incident Angle ◽  
Deposition Process ◽  
Glancing Angle Deposition ◽  
Glancing Angle ◽  
Physical Deposition ◽  
Proper Design ◽  
Angle Deposition ◽  
Nanoporous Structures

Abstract This paper presents the optimization for obtaining ultra-high aspect ratio nanostructures by GLancing Angle Deposition (GLAD). GLAD is a bottom-up, physical deposition process for creating nanometer-level features by shadows cast by seeds on the substrate at high incident angles. Based on the seeds used, GLAD can be categorized into two types: GLAD with natural seeds and pre-defined seeds (pre-seeds). When natural seeds are used, the seeds are randomly distributed with sub-100 nm feature sizes, and the percent coverage of the substrate is determined simply by the incident angle of the vapor. When the pre-seeds are used, the features can be redistributed and regrouped to generate new periodic nanostructures. This paper discusses how to obtain ultra-high aspect ratio nanopillars from natural seeds and nanoribbons from pre-defined line seeds by GLAD. In the discussion on GLAD with natural seeds, a study on the dependence of the aspect ratio on the incident angle is provided; resolvable nanopillars are obtained with aspect ratio over 1:20, and the growth mechanism is proposed for pillars with high deposition angles. Next, line seeds used in the GLAD process for creating high aspect ratio nanoribbons are discussed. Proper design and process parameters are discussed for controlling the morphologies of the nanoribbons. The ultra-high aspect ratio nanostructures are potentially used for applications including sensing, surface property alteration, and the creation of nanoporous structures.

scholarly journals Glancing Angle Deposition of Zn-Doped Calcium Phosphate Coatings by RF Magnetron Sputtering

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 220 ◽  
Author(s):  
Konstantin Prosolov ◽  
Olga Belyavskaya ◽  
Juergen Linders ◽  
Kateryna Loza ◽  
Oleg Prymak ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Tilt Angle ◽  
Antibacterial Effect ◽  
Rf Magnetron Sputtering ◽  
Scratch Resistance ◽  
Glancing Angle Deposition ◽  
Calcium Phosphate Coating ◽  
Si Substrates ◽  
Glancing Angle ◽  
Angle Deposition

Zn-substituted hydroxyapatite with antibacterial effect was used in radiofrequency (RF) magnetron deposition of calcium phosphate coating onto Ti- and Si-inclined substrates. The development of surface nanopatterns for direct bacteria killing is a growing area of research. Here, we combined two approaches for possible synergetic antibacterial effect by manufacturing a patterned surface of Zn-doped calcium phosphate using glancing angle deposition (GLAD) technique. A significant change in the coating morphology was revealed with a substrate tilt angle of 80°. It was shown that an increase in the coating crystallinity for samples deposited at a tilt angle of 80° corresponds to the formation of crystallites in the bulk structure of the thin film. The variation in the coating thickness, uniformity, and influence of sputtered species energy on Si substrates was analyzed. Coatings deposited on tilted samples exhibit higher scratch resistance. The coating micro- and nano-roughness and overall morphology depended on the tilt angle and differently affected the rough Ti and smooth Si surfaces. GLAD of complex calcium phosphate material can lead to the growth of thin films with significantly changed morphological features and can be utilized to create self-organized nanostructures on various types of surfaces.

scholarly journals METAL-TO-DIELECTRIC TRANSITION INDUCED BY ANNEALING OF ORIENTED TITANIUM THIN FILMS

2013 ◽  
Vol 06 (01) ◽  
pp. 1250051 ◽  
Author(s):  
AURÉLIEN BESNARD ◽  
NICOLAS MARTIN ◽  
FABRICE STHAL ◽  
LUC CARPENTIER ◽  
JEAN-YVES RAUCH
Keyword(s):  
Thin Films ◽  
Incident Angle ◽  
Annealing Treatment ◽  
Glancing Angle Deposition ◽  
Gradual Transition ◽  
Dc Magnetron Sputtering ◽  
Glancing Angle ◽  
Titanium Thin Films ◽  
Angle Deposition ◽  
Dielectric Transition

Titanium thin films were deposited by DC magnetron sputtering. The glancing angle deposition (GLAD) method was implemented to prepare two series of titanium films: perpendicular and oriented columnar structures. The first series was obtained with a conventional incident angle α of the sputtered particles (α = 0°), whereas the second one used a grazing incident angle α = 85°. Afterwards, the films were annealed in air using six cycles of temperature ranging from 293 K to 773 K. DC electrical conductivity was measured during the annealing treatment. Films deposited by conventional sputtering (α = 0°) kept a typical metallic-like behavior versus temperature (σ300 K = 2.0 × 106 S m-1 and TCR293 K = 1.52 × 10-3 K-1), whereas those sputtered with α = 85° showed a gradual transition from metal to dielectric. Such a transition was mainly attributed to the high porous structure, which favors the oxidation of titanium films to tend to the TiO2 compound.

Epitaxial growth of copper nanowire arrays grown on H-terminated Si(110) using glancing-angle deposition

2004 ◽  
Vol 19 (12) ◽  
pp. 3620-3625 ◽  
Author(s):  
H. Alouach ◽  
G.J. Mankey
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Growth ◽  
Glancing Angle Deposition ◽  
Nanowire Arrays ◽  
Angle Of Incidence ◽  
X Ray ◽  
Copper Nanowire ◽  
Glancing Angle ◽  
Angle Deposition ◽  
Deposition Angle

We report the growth of epitaxial nanowire arrays using the technique of glancing- angle deposition with substrate rotation. Epitaxial copper nanowire arrays were deposited on H-terminated Si(110) using electron beam evaporation. The nanowire arrays were characterized by x-ray diffraction, atomic force microscopy, and scanning electron microscopy. Individual nanowires were confirmed to be single crystalline by examination with transmission electron microscopy. The epitaxial growth involves twin formation with the epitaxial orientation relationships: Cu(111)//Si(110) with Cu[110]//Si[001] and Cu[110//Si[001] for each of the twins. As the angle of incidence is increased, Cu grows as isolated columns with a spacing that increases as the angle of incidence is increased. However, the thickness limit for epitaxial growth is reduced as the angle of incidence is increased, and it is reduced to approximately 300 nm for a deposition angle of 75°. The x-ray rocking curves for samples deposited at increasing polar angles show steadily improving crystal orientation up to a deposition angle of about 35°. Beyond 65° deposition angle, the rocking curves show significantly sharper split diffraction peaks indicating that there are distinct orientations. In addition, the split peaks have a much lower full width at half maximum. The observed behavior is explained based on arguments involving unidirectional diffusion arising from adatom parallel momentum.

scholarly journals Nanocolumnar CdS thin films grown by glancing angle deposition from a sublimate vapor effusion source

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
L. G. Daza ◽  
R. Castro Rodríguez ◽  
M. Cirerol Carrillo ◽  
E.A. Martín Tovar ◽  
J. Méndez- Gamboa ◽  
...  
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Velocity Ratio ◽  
Wavelength Region ◽  
Glancing Angle Deposition ◽  
Hexagonal Structure ◽  
Deposition Flux ◽  
Glancing Angle ◽  
Cds Thin Films ◽  
Angle Deposition

The glancing angle Deposition (GLAD) technique was used to grow cadmium sulfide (CdS) thin films on glass and indium tin oxide (ITO) coated glass substrates from a sublimate vapor effusion source. The samples were prepared under different incident deposition flux angles (a) of 0°, 20° and 80°, while both the substrate and the source were under rotation. The temperature of the source was 923.15 K. Scanning electron microscopy images showed that the GLAD method combined with the source produced dense nanocolumnar shaped structures with height and diameters of ~200 and ~30 nm respectively. The deposited films showed a hexagonal structure with preferential (002) plane orientation and crystallites sizes between ~25 nm and ~35 nm. A maximum solar weighted transmission of ~92% was obtained for the sample prepared at a =80°, with a substrate/source rotation velocity ratio of 55/20 in the wavelength region of 400-900 nm. The average band gap energy of the films was 2.42 eV. Refractive indexes between ~1.4 and ~2.4 at a 550 nm the wavelength were also obtained.

Transmission Electron Microscopy characterization of epitaxial III-V semiconductor thin films grown on Si(100) by ion-assisted deposition

1990 ◽  
Vol 48 (4) ◽  
pp. 686-687
Author(s):  
L. Hultman ◽  
C.-H. Choi ◽  
R. Kaspi ◽  
R. Ai ◽  
S.A. Barnett
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
High Energy ◽  
Nucleation Mechanism ◽  
Layer By Layer ◽  
Extended Defect ◽  
Island Formation ◽  
Si Substrates ◽  
Transmission Electron

III-V semiconductor films nucleate by the Stranski-Krastanov (SK) mechanism on Si substrates. Many of the extended defects present in the films are believed to result from the island formation and coalescence stage of SK growth. We have recently shown that low (-30 eV) energy, high flux (4 ions per deposited atom), Ar ion irradiation during nucleation of III-V semiconductors on Si substrates prolongs the 1ayer-by-layer stage of SK nucleation, leading to a decrease in extended defect densities. Furthermore, the epitaxial temperature was reduced by >100°C due to ion irradiation. The effect of ion bombardment on the nucleation mechanism was explained as being due to ion-induced dissociation of three-dimensional islands and ion-enhanced surface diffusion.For the case of InAs grown at 380°C on Si(100) (11% lattice mismatch), where island formation is expected after ≤ 1 monolayer (ML) during molecular beam epitaxy (MBE), in-situ reflection high-energy electron diffraction (RHEED) showed that 28 eV Ar ion irradiation prolonged the layer-by-layer stage of SK nucleation up to 10 ML. Otherion energies maintained layer-by-layer growth to lesser thicknesses. The ion-induced change in nucleation mechanism resulted in smoother surfaces and improved the crystalline perfection of thicker films as shown by transmission electron microscopy and X-ray rocking curve studies.

scholarly journals Fabrication of a liquid cell for in situ transmission electron microscopy

Microscopy ◽  
2020 ◽  
Author(s):  
Xiaoguang Li ◽  
Kazutaka Mitsuishi ◽  
Masaki Takeguchi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cost Effective ◽  
Production Method ◽  
Microscopy Imaging ◽  
Transmission Electron ◽  
In Situ Electron Microscopy ◽  
Liquid Cell ◽  
Si Wafer

Abstract Liquid cell transmission electron microscopy (LCTEM) enables imaging of dynamic processes in liquid with high spatial and temporal resolution. The widely used liquid cell (LC) consists of two stacking microchips with a thin wet sample sandwiched between them. The vertically overlapped electron-transparent membrane windows on the microchips provide passage for the electron beam. However, microchips with imprecise dimensions usually cause poor alignment of the windows and difficulty in acquiring high-quality images. In this study, we developed a new and efficient microchip fabrication process for LCTEM with a large viewing area (180 µm × 40 µm) and evaluated the resultant LC. The new positioning reference marks on the surface of the Si wafer dramatically improve the precision of dicing the wafer, making it possible to accurately align the windows on two stacking microchips. The precise alignment led to a liquid thickness of 125.6 nm close to the edge of the viewing area. The performance of our LC was demonstrated by in situ transmission electron microscopy imaging of the dynamic motions of 2-nm Pt particles. This versatile and cost-effective microchip production method can be used to fabricate other types of microchips for in situ electron microscopy.

Photo‐Induced Self‐Cleaning and Wettability in TiO 2 Nanocolumn Arrays Obtained by Glancing‐Angle Deposition with Sputtering

2021 ◽  
pp. 2100071
Author(s):  
Fernando Fresno ◽  
María U. González ◽  
Lidia Martínez ◽  
Marcial Fernández‐Castro ◽  
Mariam Barawi ◽  
...  
Keyword(s):  
Glancing Angle Deposition ◽  
Glancing Angle ◽  
Self Cleaning ◽  
Angle Deposition
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