Method for noncontact measurement of 2DEG mobility and carrier density in AlGaN/GaN on semi-insulating wafers

2021 ◽  
Author(s):  
Marshall Wilson ◽  
Dmitriy Marinskiy ◽  
Jacek Lagowski ◽  
Carlos Almeida ◽  
Alexandre Savtchouk ◽  
...  
Keyword(s):  
Sheet Resistance ◽  
Carrier Density ◽  
Wafer Level ◽  
Zero Bias ◽  
Full Depletion ◽  
A Charge ◽  
Charge Deposition ◽  
Method Analysis ◽  
Bias Condition

Abstract We present a charge-assisted sheet resistance technique for noncontact wafer level determination of 2DEG mobility vs. sheet carrier density without any test structures or gates. Instead, the electrical biasing of 2DEG is provided by surface charge deposition, using a corona charging method. Analysis of the sheet resistance vs. deposited charge identifies the 2DEG full depletion condition and enables calculation of the 2DEG sheet carrier density required for the mobility. Results for AlGaN/GaN heterostructures on semi-insulating SiC and sapphire substrates show good agreement with Hall results at a zero-bias condition.

Determination of Epsilon Aminocaproic Acid Based on Charge Transfer Complexation with p-Nitrophenlol by Spectrophotometry

2020 ◽  
Vol 16 ◽  
Author(s):  
Sheng-Yun Li ◽  
Fang Tian
Keyword(s):  
Charge Transfer ◽  
Aminocaproic Acid ◽  
Concentration Limit ◽  
Official Method ◽  
Good Precision ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
A Charge ◽  
Epsilon Aminocaproic Acid

: A spectrophotometry was investigated for the determination of epsilon aminocaproic acid (EACA) with p-nitrophenol (PNP). The method was based on a charge transfer (CT) complexation of this drug as n-electron donor with π-acceptor PNP. Experiment indicated that the CT complexation was carried out at room temperature for 10 minutes in dimethyl sulfoxide solvent. The spectrum obtained for EACA/PNP system showed the maximum absorption band at wavelength of 425 nm. The stoichiometry of the CT complex was found to be 1:1 ratio by Job’s method between the donor and the acceptor. Different variables affecting the complexation were carefully studied and optimized. At the optimum reaction conditions, Beer’s law was obeyed in a concentration limit of 1～6 µg mL-1. The relative standard deviation was less than 2.9%. The apparent molar absoptivity was determined to be 1.86×104 L mol-1cm-1 at 425 nm. The CT complexation was also confirmed by both FTIR and 1H NMR measurements. The thermodynamic properties and reaction mechanism of the CT complexation have been discussed. The developed method could be applied successfully for the determination of the studied compound in its pharmaceutical dosage forms with a good precision and accuracy compared to official method as revealed by t- and F-tests.

scholarly journals Determination of Carrier Density and Dynamics via Magnetoelectroluminescence Spectroscopy in Resonant-Tunneling Diodes

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
E.R. Cardozo de Oliveira ◽  
A. Naranjo ◽  
A. Pfenning ◽  
V. Lopez-Richard ◽  
G.E. Marques ◽  
...  
Keyword(s):  
Carrier Density ◽  
Resonant Tunneling ◽  
Resonant Tunneling Diodes ◽  
Tunneling Diodes

Heteroarray of cobalt(II)tetrasulfophthalocyanine and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin: synthesis, isolation and electronic properties

2012 ◽  
Vol 16 (02) ◽  
pp. 244-249 ◽  
Author(s):  
Thiago T. Tasso ◽  
Wania C. Moreira
Keyword(s):  
Electronic Properties ◽  
Spectroscopic Characterization ◽  
Charge Transfer Process ◽  
Isolation And Purification ◽  
Electronic Densities ◽  
Porphyrin Synthesis ◽  
A Charge ◽  
Job's Method ◽  
First Time

Porphyrin and phthalocyanine macrocycles with ionic substituents can form mixed assemblies with interesting electronic properties for potential application on the development of new devices. This paper reports the synthesis, isolation and purification of heteroaggregate formed by cobalt(II) 4,4′,4″,4‴-tetrasulfophthalocyanine (CoTsPc) and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin (CoTMPyP), followed by its spectroscopic characterization. Spectroscopic titration, performed with a CoTsPc water/acetone solution, allowed the use of Job's method for determination of the heteroaggregates stoichiometry. The Job's plot revealed the formation of only one predominant heterocomplex in solution, containing two CoTsPc molecules in terminal positions and a central CoTMPyP one. For the first time, a method for isolation and purification of a mixed ionic array has been reported in the literature. The triad's electronic spectrum is quite different from the sum of the macrocycles isolated spectra, due to the overlap of their electronic densities and a charge transfer process between CoTsPc and CoTMPyP.

Determination of the charge of Al13 Keggin oligocations intercalated into synthetic hectorite

2019 ◽  
Vol 74 (1) ◽  
pp. 85-90
Author(s):  
Marius Schöttle ◽  
Dominik Schuchardt ◽  
Andreas Edenharter ◽  
Sebastian Koch ◽  
Jürgen Senker ◽  
...  
Keyword(s):  
Reaction Time ◽  
Solid State ◽  
Ir Spectroscopy ◽  
Cation Exchange ◽  
Elemental Analysis ◽  
Crystalline Phase ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
A Charge

AbstractApplying a nematic liquid crystalline phase of a synthetic Na-hectorite with layer separations >100 nm, the reaction time for pillaring with Al13 Keggin oligocation could be reduced to seconds ensuring that cation exchange is controlled by thermodynamics. With this material at hand we are able to resolve the long-standing dispute regarding the charge of intercalated Keggin oligocations. Micropore sizes as determined by physisorption isotherms, adsorption isotherms obtained via elemental analysis, and results of 27Al solid-state NMR and pyridine probe IR spectroscopy favor a charge of +7 for the Al13 pillars intercalated into hectorite unaltered.

scholarly journals Evaluation of Inhomogeneous Resistive Layers by a Four Point Method

1981 ◽  
Vol 7 (4) ◽  
pp. 211-216
Author(s):  
György Fodor ◽  
Miklós Szilágyi ◽  
László Zombory
Keyword(s):  
Sheet Resistance ◽  
Point Method ◽  
Narrow Strip ◽  
Resistive Layer

This paper describes the determination of the sheet resistance of a narrow strip located in a homogeneous resistive layer of different resistivity. The application of the method for the evaluation of inhomogeneous layers used for thermoprinter head production is discussed.

The Role of Surface Physical Properties on Blood Compatibility of Titanium Oxide Films Synthesized by Unbalanced Magnetron Sputtering

2005 ◽  
Vol 288-289 ◽  
pp. 311-314 ◽  
Author(s):  
Yong Xiang Leng ◽  
Ping Yang ◽  
Ji Yong Chen ◽  
Lan Xin Xu ◽  
An Sha Zhao ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Physical Properties ◽  
Titanium Oxide ◽  
Sheet Resistance ◽  
Oxygen Pressure ◽  
Carrier Density ◽  
Blood Compatibility ◽  
Oxide Films ◽  
X Ray ◽  
Titanium Oxide Films

Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper we describe our work on improving blood compatibility with Ti–O thin films prepared by unbalanced DC magnetron sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), SEM, sheet resistance tests, and Hall effect measurements. The sheet resistance of the titanium oxide samples increased with oxygen pressure and shows a sharp increase when only TiO2 exists in the films. The band gap, carrier density and sheet resistance of the titanium oxide films synthesized at different oxygen pressure are different. These properties affect blood compatibility significantly. We suggest that the semiconducting nature of n-type Ti–O films with bandgap 3.0~3.2 eV, sheet resistance greater than 1 Ω.cm and carrier density of about 1.17 x 1016cm-2 leads to their excellent blood compatibility.

Afterword Quilting the Black-Eyed Pea

2019 ◽  
pp. 257-272
Author(s):  
Michael O. West
Keyword(s):  
Social Contract ◽  
The United States ◽  
The Self ◽  
Declaration Of Independence ◽  
The Social ◽  
The Us ◽  
The Republic ◽  
To Come ◽  
A Charge

It is a truism that black folk in the United States are an international people. From the beginning of the republic, they were compelled by force of domestic (national) circumstances to internationalize their struggle for liberation, the founders having excluded them from the US social contract. The initial affidavit of exclusion is right there in the inaugural document of the social contract, the Declaration of Independence, which, ever so cryptically, damned the king of England for having “excited domestic insurrections amongst us.” This was an attack on the self-emancipatory activities of the enslaved descendants of Africa, who were exploiting the chaos caused by the anticolonial rebellion to claim their freedom, sometimes in cahoots with the British colonialists. Unable or unwilling to confront their own contradictions, the authors of the Declaration of Independence condemned the self-determination of the slaves as the doing of outside agitators, a charge that would be hurled at African American movements and activists for generations to come—up to the present time, in fact....

scholarly journals Impact of non-uniform carrier density on the determination of metal induced recombination losses

2019 ◽  
Author(s):  
David Herrmann ◽  
Andreas Fell ◽  
Hannes Höffler ◽  
Sabrina Lohmüller ◽  
Andreas Wolf
Keyword(s):  
Carrier Density

scholarly journals Advances in Monte-Carlo code TRIPOLI-4®’s treatment of the electromagnetic cascade

2018 ◽  
Vol 170 ◽  
pp. 01008
Author(s):  
Davide Mancusi ◽  
Alice Bonin ◽  
François-Xavier Hugot ◽  
Fadhel Malouch
Keyword(s):  
Monte Carlo ◽  
Nuclear Reactor ◽  
Thick Target ◽  
Monte Carlo Code ◽  
Reactor Physics ◽  
Validation And Verification ◽  
Electron Positron ◽  
A Charge ◽  
Charge Deposition ◽  
Nuclear Instrumentation

TRIPOLI-4® is a Monte-Carlo particle-transport code developed at CEA-Saclay (France) that is employed in the domains of nuclear-reactor physics, criticality-safety, shielding/radiation protection and nuclear instrumentation. The goal of this paper is to report on current developments, validation and verification made in TRIPOLI-4 in the electron/positron/photon sector. The new capabilities and improvements concern refinements to the electron transport algorithm, the introduction of a charge-deposition score, the new thick-target bremsstrahlung option, the upgrade of the bremsstrahlung model and the improvement of electron angular straggling at low energy. The importance of each of the developments above is illustrated by comparisons with calculations performed with other codes and with experimental data.

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