scholarly journals Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN

2013 ◽  
Vol 113 (1) ◽  
pp. 013502 ◽  
Author(s):  
S. Schöche ◽  
T. Hofmann ◽  
V. Darakchieva ◽  
N. Ben Sedrine ◽  
X. Wang ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Hall Effect ◽  
Vacuum Ultraviolet ◽  
Free Charge Carrier ◽  
Effect Study ◽  
Free Charge ◽  
Optical Hall Effect ◽  
Mg Doped

scholarly journals Cavity-enhanced optical Hall effect in two-dimensional free charge carrier gases detected at terahertz frequencies

2015 ◽  
Vol 40 (12) ◽  
pp. 2688 ◽  
Author(s):  
S. Knight ◽  
S. Schöche ◽  
V. Darakchieva ◽  
P. Kühne ◽  
J.-F. Carlin ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Hall Effect ◽  
Free Charge Carrier ◽  
Two Dimensional ◽  
Free Charge ◽  
Terahertz Frequencies ◽  
Carrier Gases ◽  
Optical Hall Effect

Infrared ellipsometry and near-infrared-to-vacuum-ultraviolet ellipsometry study of free-charge carrier properties in In-polar p-type InN

2012 ◽  
Vol 1396 ◽  
Author(s):  
Stefan Schöche ◽  
Tino Hofmann ◽  
Nebiha Ben Sedrine ◽  
Vanya Darakchieva ◽  
Xinqiang Wang ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Near Infrared ◽  
Vacuum Ultraviolet ◽  
Free Charge Carrier ◽  
Plasmon Coupling ◽  
Free Charge ◽  
Infrared Ellipsometry ◽  
Parameterized Model ◽  
P Type ◽  
Mg Doped

ABSTRACTWe apply infrared spectroscopic ellipsometry (IRSE) in combination with near-infrared to vacuum-ultraviolet ellipsometry to study the concentration and mobility of holes in a set of Mg-doped In-polar InN samples of different Mg-concentrations. P-type behavior is found in the IRSE spectra for Mg-concentrations between 1x1018 cm-3 and 3x1019 cm-3. The free-charge carrier parameters are determined using a parameterized model that accounts for phonon-plasmon coupling. From the NIR-VUV data information about layer thicknesses, surface roughness, and structural InN layer properties are extracted and related to the IRSE results.

scholarly journals In-situ terahertz optical Hall effect measurements of ambient effects on free charge carrier properties of epitaxial graphene

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Sean Knight ◽  
Tino Hofmann ◽  
Chamseddine Bouhafs ◽  
Nerijus Armakavicius ◽  
Philipp Kühne ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Hall Effect ◽  
Free Charge Carrier ◽  
Epitaxial Graphene ◽  
Free Charge ◽  
Hall Effect Measurements ◽  
Optical Hall Effect

scholarly journals Critical View on Buffer Layer Formation and Monolayer Graphene Properties in High-Temperature Sublimation

2021 ◽  
Vol 11 (4) ◽  
pp. 1891
Author(s):  
Vallery Stanishev ◽  
Nerijus Armakavicius ◽  
Chamseddine Bouhafs ◽  
Camilla Coletti ◽  
Philipp Kühne ◽  
...  
Keyword(s):  
High Temperature ◽  
Charge Carrier ◽  
Buffer Layer ◽  
Free Charge Carrier ◽  
Monolayer Graphene ◽  
Free Charge ◽  
Layer Formation ◽  
Free Hole ◽  
Sublimation Growth ◽  
Insulating Substrates

In this work we have critically reviewed the processes in high-temperature sublimation growth of graphene in Ar atmosphere using closed graphite crucible. Special focus is put on buffer layer formation and free charge carrier properties of monolayer graphene and quasi-freestanding monolayer graphene on 4H–SiC. We show that by introducing Ar at higher temperatures, TAr, one can shift the formation of the buffer layer to higher temperatures for both n-type and semi-insulating substrates. A scenario explaining the observed suppressed formation of buffer layer at higher TAr is proposed and discussed. Increased TAr is also shown to reduce the sp3 hybridization content and defect densities in the buffer layer on n-type conductive substrates. Growth on semi-insulating substrates results in ordered buffer layer with significantly improved structural properties, for which TAr plays only a minor role. The free charge density and mobility parameters of monolayer graphene and quasi-freestanding monolayer graphene with different TAr and different environmental treatment conditions are determined by contactless terahertz optical Hall effect. An efficient annealing of donors on and near the SiC surface is suggested to take place for intrinsic monolayer graphene grown at 2000 ∘C, and which is found to be independent of TAr. Higher TAr leads to higher free charge carrier mobility parameters in both intrinsically n-type and ambient p-type doped monolayer graphene. TAr is also found to have a profound effect on the free hole parameters of quasi-freestanding monolayer graphene. These findings are discussed in view of interface and buffer layer properties in order to construct a comprehensive picture of high-temperature sublimation growth and provide guidance for growth parameters optimization depending on the targeted graphene application.

Selective observation of transverse optical phonons of Au modes to evaluate free charge carrier parameters in β-Ga2O3 substrate and homoepitaxial film

2021 ◽  
Vol 118 (25) ◽  
pp. 252101
Author(s):  
Takeyoshi Onuma ◽  
Kohei Sasaki ◽  
Tomohiro Yamaguchi ◽  
Tohru Honda ◽  
Akito Kuramata ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Free Charge Carrier ◽  
Transverse Optical ◽  
Optical Phonons ◽  
Free Charge ◽  
Homoepitaxial Film

Free charge carrier repartition over the surface of photosensitive materials: Why and how to manage?

2008 ◽  
Vol 78 (5) ◽  
pp. 1070-1080 ◽  
Author(s):  
A. A. Evstratov ◽  
C. Chis ◽  
A. A. Malygin ◽  
J. -M. Taulemesse ◽  
P. Gaudon ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Free Charge Carrier ◽  
Free Charge

SFGP 2007 - Photosensitive Composite Disordered Nanostructures over Acceptor Supports: Selective Free Charge Carrier Generators for Environmental Applications

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Cristain Chis ◽  
Alexis Evstratov
Keyword(s):  
Charge Carrier ◽  
Free Charge Carrier ◽  
Charge Carriers ◽  
Environmental Applications ◽  
Free Charge ◽  
Active Components ◽  
Active Materials ◽  
Photocatalytic Removal ◽  
Volatile Organic

Amorphous and low-ordered photosensitive materials are not usually considered to be promising photocatalytic agents because of extremely short free charge carrier (FCC) lifetimes in their active components deprived of well-defined electronic structures. Using active supports favoring an efficient FCC separation in situ, it is possible to protect free charge carriers from the immediate recombination, so even the disordered photosensitive composites can be provided with important photocatalytic capacities. The examples of some environmental applications of this type of active materials, such as volatile organic compound (VOC) photocatalytic removal and bacteria sterilization, are presented in this paper.

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