Raman and AFM mapping studies of photo-induced crystallization in a-Se films: substrate strain and thermal effects

2014 ◽  
Vol 92 (7/8) ◽  
pp. 728-731 ◽  
Author(s):  
G.P. Lindberg ◽  
T. O’Loughlin ◽  
N. Gross ◽  
A. Reznik ◽  
S. Abbaszadeh ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Thermal Effects ◽  
Onset Time ◽  
Interface Layer ◽  
Amorphous Selenium ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Soft Polymer ◽  
Induced Crystallization

Photo-induced crystallization (PC) is studied in amorphous selenium (a-Se) films deposited on glass with and without intermediate layers of indium tin oxide or polymer material. The spatial profile of PC domains is examined by co-localized scanning atomic force microscopy and Raman mapping. We also explore the thermal behavior of the onset and growth of PC in the a-Se films by Raman spectroscopy measurements at temperatures spanning the glass transition (Tg ∼ 313 K). In many films the onset time for PC shows a surprising discontinuity near Tg. Inserting a thin polyimide layer between the a-Se film and the substrate inhibits PC. Our results indicate that adhesion to a rigid substrate is important for promoting PC in a-Se films. We find that the discontinuities in the PC onset times, the shape of the mapping profiles, and the effects of having a soft polymer interface layer can be understood by a model that takes account of the substrate shear strain and its relaxation near Tg.

scholarly journals Microwave Spectroscopic Detection of Human Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 118
Author(s):  
Rodica Ionescu ◽  
Raphael Selon ◽  
Nicolas Pocholle ◽  
Lan Zhou ◽  
Anna Rumyantseva ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Stress Disorders ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Conductive Glass ◽  
Hsp70 Protein ◽  
Atomic Force ◽  
Ito Glass ◽  
First Time ◽  
Human Heat Shock Protein

Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.

Transparent Conducting Indium-Tin-Oxide Thin Film with Extremely Flatted Surface

2001 ◽  
Vol 666 ◽  
Author(s):  
Hiromichi Ohta ◽  
Masahiro Orita ◽  
Masahiro Hirano ◽  
Hideo Hosono
Keyword(s):  
Thin Film ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Film Growth ◽  
Oxide Thin Film ◽  
Force Microscopy ◽  
Atomic Force ◽  
Out Of Plane ◽  
Key Factor ◽  
Surface Microstructures

ABSTRACTIndium-tin-oxide films were grown hetero-epitaxially on YSZ surface at a substrate temperature of 900 °C, and their surface microstructures were observed by using atomic force microscopy. ITO films grown on (111) surface of YSZ exhibited very high crystal quality; full width at half maximum of out-of-plane rocking curve was 54 second. The ITO was grown spirally, with flat terraces and steps corresponding to (222) plane spacing of 0.29 nm. Oxygen pressure during film growth is another key factor to obtain atomically flat surfaced ITO thin film.

scholarly journals Investigating the Nanocomposite Thin Films of Hematite α-Fe2O3 and Nafion for Cholesterol Biosensing Applications

2020 ◽  
Vol 2 ◽  
Author(s):  
Indra Sulania ◽  
R. Blessy Pricilla ◽  
G. B. V. S. Lakshmi
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Differential Pulse ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Enzyme Substrate ◽  
Atomic Force ◽  
Nanocomposite Thin Films ◽  
Multi Phase ◽  
Cholesterol Biosensor

Nanocomposite materials are multi-phase materials, usually solids, which have two or more component materials having different chemical and physical properties. When blended together, a newer material is formed with distinctive properties which make them an eligible candidate for many important applications. In the present study, thin films of nafion (polymer) and hematite or α-Fe2O3 (nanoparticles) nanocomposite is fabricated on indium tin oxide (ITO) coated glass substrates, due to its enhanced ionic conductivity, for cholesterol biosensor applications. Scanning electron microscopy and Atomic force microscopy revealed the formation of nanorod structured α-Fe2O3 in the films. The cyclic voltammetry (CV) studies of nafion-α-Fe2O3/ITO revealed the redox properties of the nanocomposites. The sensing studies were performed on nafion-α-Fe2O3/CHOx/ITO bioelectrode using differential pulse voltammetry (DPV) at various concentrations of cholesterol. The enzyme immobilization leaded to the selective detection of cholesterol with a sensitivity of 64.93 × 10−2 μA (mg/dl)−1 cm−2. The enzyme substrate interaction (Michaelis–Menten) constant Km, was obtained to be 19 mg/dl.

Growth of GaN epilayers on Si(111) substrates using multiple buffer layers

2001 ◽  
Vol 693 ◽  
Author(s):  
P.R. Hageman ◽  
S. Haffouz ◽  
A. Grzegorczk ◽  
V. Kirilyuk ◽  
P.K. Larsen
Keyword(s):  
Atomic Force Microscopy ◽  
Epitaxial Films ◽  
Buffer Layers ◽  
High Quality ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Vapor Deposition Technique

AbstractWe present a study of the growth of high quality GaN films on Si(111) substrates by MetalOrganic Chemical Vapor Deposition technique. In order to improve the quality of the epitaxial films we introduced different nucleation or buffer layers and combinations of them. Our results obtained on an optimized AlN nucleation layer will serve as reference point. In order to improve the quality of the epitaxial films we introduced different combinations of nucleation and intermediate layers. The first combination consists of an optimized AlN nucleation layer followed by a 1 m-thick GaN film, on which we deposited SixNy/GaN intermediate layers. Based on the optimized AlN nucleation layer, we introduced AlGaN/GaN superlattices or AlN intermediate buffer layers. Additionally, we present results on the modification the Si(111) surface with NH3 to promote nucleation from selective GaN islands. In all experiments the total thickness of the GaN epilayers was 3 m m. X-ray diffraction, photoluminescence, Hall measurements and atomic force microscopy were used in order to elucidate the effectiveness of these growth processes. For the most successful deposition scheme, the one with the SixNy/GaN intermediate layers, the resulting GaN layers are of high quality as compared to the other methods. The donor bound exciton, which dominates the photoluminescence spectrum, showed a full width at half maximum (FWHM) of about 50 meV at room temperature and 10 meV at 4K. The FWHM of the symmetric (0002) rocking curves in w-scan is about 640 arcsec. The root-mean-square roughness, as measured by atomic force microscopy, does not exceed 10 Å.

scholarly journals Chemosensing on Miniaturized Plasmonic Substrates

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 275
Author(s):  
Pengcheng Wang ◽  
Rodica Elena Ionescu
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Localized Surface Plasmon Resonance ◽  
Thin Layers ◽  
Localized Surface Plasmon ◽  
Force Microscopy ◽  
Atomic Force ◽  
Model Molecule ◽  
First Time ◽  
Scanning Electron

Round, small-sized coverslips were coated for the first time with thin layers of indium tin oxide (ITO, 10–40 nm)/gold (Au, 2–8 nm) and annealed at 550 °C for several hours. The resulting nanostructures on miniaturized substrates were further optimized for the localized surface plasmon resonance (LSPR) chemosensing of a model molecule—1,2-bis-(4-ppyridyl)-ethene (BPE)—with a detection limit of 10−12 M BPE in an aqueous solution. All the fabrication steps of plasmonic-annealed platforms were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Initial Stage of CaF2/Si(111) Epitaxy Investigated by Lateral/Atomic Force Microscopy

2003 ◽  
Vol 10 (04) ◽  
pp. 605-610 ◽  
Author(s):  
C. R. Wang ◽  
B. H. Müller ◽  
K. R. Hofmann
Keyword(s):  
Atomic Force Microscopy ◽  
Silicon Surface ◽  
High Growth ◽  
Lateral Force ◽  
Interface Layer ◽  
Atmospheric Environment ◽  
Mbe Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Initial Stage

The initial stages of the high temperature (~ 700°C) MBE growth of CaF 2 on well-oriented Si(111) substrates have been studied by atomic force microscopy (AFM) and lateral force microscopy (LFM) in the atmosphere. At these temperatures CaF 2 molecules react with the silicon surface and form a CaF 1–Si interface layer. The CaF 1 layer covers the silicon surface completely before CaF 2 islands start to form, and it is stable in the atmospheric environment for some days. The subsequent growth on this interface layer results in multilayer CaF 2 islands (about 5 TL in height). The friction force experienced by the Si tip was found to be larger on the CaF 1 interface layer than that on the CaF 2 layer and allows a direct distinction between the CaF 1–Si interface layer and CaF 2. Two different types of islands are observed. One has a regular shape with a flat top surface; the other has an irregular shape and exhibits a 0.3–0.6-nm-high corrugation. We suppose that the formation of disturbed islands can be attributed to the dissociation of the CaF 1 interface at the growth temperature of 700°C. These results suggest that high growth temperatures (> 600°C) do not always result in the best CaF 2 film.

Preparation and Properties of Dy Doped La and Sc Solution of BiFeO3 Film

2013 ◽  
Vol 537 ◽  
pp. 109-113
Author(s):  
Xi Wei Qi ◽  
Xiao Yan Zhang ◽  
Xuan Wang ◽  
Hai Bin Sun ◽  
Jian Quan Qi
Keyword(s):  
Thin Film ◽  
Indium Tin Oxide ◽  
Doping Level ◽  
Sol Gel ◽  
Second Phase ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Ito Glass ◽  
Dy Doping

A series of Dy doped La and Sc solution of BiFeO3 thin films have been prepared by using spin-coating process on conductive indium tin oxide (ITO)/glass substrates, which a simple sol-gel possess is applied and annealed at 500°C. With the increase of content of Dy, the strongest peak (110) of La and Sc solution BiFeO3 film tends to further broaden. There is no second phase existence within the present Dy doping level. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 film was about 370 nm. For Dy doping level is 0.05, the maximum double remanent polarization 2Pr of as-prepared BiFeO3 thin film is15.44 μC/cm2. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of as-prepared BiFeO3 thin film is 2.11 nm. The dielectric constant of as-prepared films tends to firstly increase and then decrease with the increase of Dy content

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