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1

High Temperature Surface Conductivity of Hydrogenated Diamond Films Exposed to Humid Air

100%

Stec K., Szroeder P., Benzhour K.

Acta Physica Polonica A

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2010

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vol. 118

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issue 3

511-514

EN

Surface conductivity of thin diamond films was measured as a function of temperature up to 450°C. Hydrogenated diamond was synthesized by chemical vapor deposition in hydrogen/carbon plasma. Low values of charge carrier activation energy ( ≈ 10 meV) were observed, when hydrogenated diamond films were exposed to the ambient humid air. However, the activation energy increased by two orders of magnitude as film temperature exceeded 300°C. We have attributed this behavior to the desorption of the H_2O adlayer. The jump of the activation energy did not occur, when experiment was performed in vacuum. We have also shown that donor doping leads to the up-shift of the Fermi level much above the acceptor-like band gap levels induced by surface C-H bonds, which cannot be compensated by transfer of electrons from diamond to the double H-H_2O layer.

2

Growth of Laser Ablated YBa_{2}Cu_{3}O_{7} Thin Films Epitaxied on (100)MgO: Influence of In-Plane Misorientations on Low and High Frequency Properties

80%

Perrin A., Guilloux-Viry M., Castel X.

Acta Physica Polonica A

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1997

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vol. 92

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issue 1

115-125

EN

The graphoepitaxial growth of c-axis YBa_{2}Cu_{3}O_{7} laser ablated thin films on (100)MgO induces a competition between two main in-plane orientations due to the large lattice mismatch: ⟨100⟩ YBa_{2}Cu_{3}O_{7} ∥ ⟨100⟩ MgO, c_{⊥ 0} notation or ⟨110⟩ YBa_{2}Cu_{3}O_{7} ∥ ⟨100⟩ MgO, c_{⊥ 45} notation. The ratio of c_{⊥ 45}/c_{⊥ 0} in-plane orientations (η), measured by X-ray diffraction φ scans, is ranging from 0.2% to 49.7% for the films reported here. Their crystalline qualities were compared on the basis of rocking curves (Δθ), electron channeling patterns and reflection high energy electron diffraction diagrams. The coexistence of c_{⊥ 0} and c_{⊥ 45} domains creates high angle grain boundaries. No degradation of T_{c}, residual resistance ratio (RRR) or ΔT_{c} is observed when η increases. In contrast, a strong correlation between microwave losses characterized by surface resistance (R_{S} at 10 GHz and 77 K), inductive losses S(χ") (surface of the χ" peak obtained in a.c. susceptibility at 119 Hz) and η was clearly evidenced. A minimum of losses was found for η between 3 and 6% suggesting the necessity of a low quantity of high angle grain boundaries for films optimization. Finally, some specific processes carried out recently in order to try to efficiently control η, then R_{S} are discussed.

3

Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

80%

Marinskiy D., Edelman P., Snider A.

Acta Physica Polonica A

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2014

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vol. 125

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issue 4

997-1002

EN

Ionic diffusion of (H_2O)_{n}^{+} and CO¯_3 on SiO_2 surfaces has been quantified using Kelvin force microscopy measurement of ion distribution change after small spot corona charge. For both positive and negative ionic species, the concentration profiles versus time follow the two-dimensional surface diffusion enabling a determination of corresponding diffusion coefficients. On a thermally grown SiO_2 surface, diffusion coefficients of (H_2O)_{n}^{+} and CO¯_3 ions were 2.2 × 10^{-11} cm^2/s and 4.8 × 10^{-12} cm^2/s, respectively. On a chemically cleaned SiO_2 surface, diffusion coefficients of (H_2O)_{n}^{+} and CO¯_3 ions were 7.5 × 10^{-9} cm^2/s and 2.4 × 10^{-9} cm^2/s, respectively. Mathematical analysis of the surface potential decay yields an additional parameter - capacitance equivalent thickness.

4

Studies of Dark Current Reduction in InAsSb Mid-Wave Infrared HOT Detectors through Two Step Passivation Technique

80%

Michalczewski K., Ivaldi F., Kubiszyn Ł., Benyahia D., Boguski J., Kębłowski A., Martyniuk P., Piotrowski J., Rogalski A.

Acta Physica Polonica A

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2017

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vol. 132

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issue 2

325-328

EN

We report on the investigation of the surface leakage current for InAs_{1-x}Sb_x (x=0.09) high operation temperature photodiode grown on GaAs substrate in accelerated short-term stability test. The electrochemical passivation technique was proposed to modify the mesa sidewalls properties and obtain anodic sulphur coating covered by SU-8 negative photoresist. The electrical behavior of sulphur anodic film, SU-8 photoresist, and unpassivated devices was compared for devices in variable area diode array test. The surface resistivity for anodic sulphur film, SU-8 and unpassivated devices are equal to 1080, 226, 10200 kΩ cm, respectively, at 150 K and 1340, 429, 2870 kΩ cm, respectively, at 150 K after an exposure of 20 h to atmosphere at 373 K. The Auger recombination process was evaluated as the main mechanism of diffusion current in HOT devices.

5

Electric Conductivity of Carbon Nanoparticles Stimulated by Electric Field

61%

Markowski D., Kempiński W., Kempiński M., Trybuła Z., Kaszyńska K., Śliwińska-Bartkowiak M.

Acta Physica Polonica A

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2010

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vol. 118

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issue 3

457-458

EN

Host-guest interactions can be the unique method of spin manipulation in nanoscale. Strong changes in spin localization are generated when potential barriers between nanographitic units of activated carbon fibers are modified by interaction with adsorbed molecules. Stronger modifications occur when dipolar guest molecules are stimulated with external electric field. We report experimental results which show the influence of electric field on the spin localization in activated carbon fibers.

6

Electrical Characterizations of Schottky Diodes οn ITO Modified by Aromatic SAMs

51%

Havare A., Okur S., Yagmurcukardes N., Can M., Aydin H., Seker M., Demic S.

Acta Physica Polonica A

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2013

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vol. 123

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issue 2

456-458

EN

In order to understand the electronic properties of the organic Schottky diode, ITO/TPD/Al and ITO/SAM/TPD/Al organic Schottky devices were fabricated to obtain current-voltage characteristics. From the slopes and y-axis intercepts of the plots, the values of the ideality factor, barrier heights of the ITO/SAM/TPD/Al diode were determined as 2.03 and 0.56 eV, respectively. The surface characterizations of modified and unmodified ITO were performed via atomic force microscopy.

7

Analysis of nonlinear electric field of hvdc wall bushing with a finite element approach

41%

Dai L., Luo L.

Open Physics

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2005

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vol. 3

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issue 4

581-590

EN

The present research intends to establish a numerical model, on the basis of a theoretical analysis, for describing and analyzing the electric field of High Voltage Direct Current (HVDC) wall bushing that demonstrates highly nonlinear characteristics. The wall bushing is subjected high voltage with nonlinear electric field and the relationship between the electric field intensity and the resistance of the insulators of the wall bushing is highly nonlinear. With a parameter design language of a Finite Element Analysis software package for carrying out the numerical calculations, the effects of the nonlinearity on the electric field can be well taken into consideration in performing the numerical assessment. A technique utilizing the numerical iteration is developed for quantifying the electric intensity of the electric field. With the model and the iteration technique established, the nonlinear characteristics of the HVDC wall bushing can be investigated with efficiency.

Refine search results

High Temperature Surface Conductivity of Hydrogenated Diamond Films Exposed to Humid Air

Growth of Laser Ablated YBa_{2}Cu_{3}O_{7} Thin Films Epitaxied on (100)MgO: Influence of In-Plane Misorientations on Low and High Frequency Properties

Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

Studies of Dark Current Reduction in InAsSb Mid-Wave Infrared HOT Detectors through Two Step Passivation Technique

Electric Conductivity of Carbon Nanoparticles Stimulated by Electric Field

Electrical Characterizations of Schottky Diodes οn ITO Modified by Aromatic SAMs

Analysis of nonlinear electric field of hvdc wall bushing with a finite element approach