Surface-reconstruction-induced changes in free-carrier scattering from the W(100) surface: An infrared surface-electromagnetic-wave study

1986 ◽  
Vol 34 (2) ◽  
pp. 692-703 ◽  
Author(s):  
D. M. Riffe ◽  
L. M. Hanssen ◽  
A. J. Sievers
Keyword(s):  
Electromagnetic Wave ◽  
Surface Reconstruction ◽  
Free Carrier ◽  
Surface Electromagnetic Wave ◽  
Carrier Scattering ◽  
Induced Changes

scholarly journals Electron mobility dependence on neutron irradiation fluence in heavily irradiated silicon

2021 ◽  
Vol 61 (2) ◽  
Author(s):  
J.V. Vaitkus ◽  
A. Mekys ◽  
Š. Vaitekonis
Keyword(s):  
Neutron Irradiation ◽  
Electron Mobility ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Radiation Detector ◽  
Forward Bias ◽  
Free Carrier ◽  
Detector Efficiency ◽  
Applied Model ◽  
Carrier Scattering

An increase of neutron irradiation fluence caused a decrease of Si radiation detector efficiency that was exceptionally well seen at 1017 neutron/cm2 fluence when the observed I–V characteristic of p-n junction under forward bias and under reverse bias became similar. Therefore the investigation of free carrier mobility could be a key experiment to understand the change of heavily irradiated silicon. The electron mobility was investigated by magnetoresistance means in microstrip silicon samples at temperature range T = 200–276 K. The analysis included the free carrier scattering by phonons, ionized impurities, dipoles and clusters and a contribution of each process was found by fitting the mobility dependence on temperature. The analysis of experimental data clearly demonstrated that the applied model did not explain the mobility in the samples irradiated to the highest fluence. Therefore a new concept of carrier transport is needed, and, as a conclusion, it could be stated that Si irradiated above 1016 cm–2 fluence (and up to 1020 cm–2) is a disordered material with the clusters.

Контроль электрофизических параметров метаматериалов методом поверхностных электромагнитных волн

2021 ◽  
pp. 51-67
Author(s):  
А.И. Казьмин ◽  
П.А. Федюнин
Keyword(s):  
Inverse Problem ◽  
Electromagnetic Wave ◽  
Radio Wave ◽  
Local Control ◽  
Negative Refraction ◽  
Test Sample ◽  
Experimental Investigations ◽  
Surface Electromagnetic Wave ◽  
New Radio ◽  
Electrophysical Parameters

Development of metamaterials has led to the search and choice of effective methods of radio-wave nondestructive testing of their electrophysical parameters. The existing approaches to testing based on extracted of effective electrophysical parameters of metamaterials from the coefficients of reflection and transmission of an electromagnetic wave have low reliability and don't provide their local control. We present the new radio-wave method of local control of complex dielectric permittivity and magnetic permeability, as well as the thickness of metamaterial plate on a metal substrate with surface microwaves. The method is based on the solution of inverse problem in the determination of effective electrophysical parameters of metamaterial from the frequency dependence of the attenuation coefficient of the field of a slow surface electromagnetic wave excited in a test sample. The electrophysical parameters of the metamaterial are represented as parametric frequency functions in accordance with the Drude-Lorentz models of dispersion, and the solution of the inverse problem is reduced to minimizing the objective function constructed based on the discrepancy between the experimental and design theoretical values of the attenuation coefficients of surface electromagnetic wave fields on a grid of discrete frequencies. The structure of a measuring complex that implements the proposed method of control is proposed. For the numerical and experimental verification of the method, a sample of a metamaterial plate based on SRR elements with a negative refraction region in the frequency band 10.06–10.64 GHz was investigated. Experimental investigations of the metamaterial demonstrated the theoretical capabilities gained with measurement of the local electrophysical parameters with relative error not greater 10 %.

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