Free-carrier mobility in GaN in the presence of dislocation walls

2001 ◽  
Vol 63 (11) ◽  
Author(s):  
J.-L. Farvacque ◽  
Z. Bougrioua ◽  
I. Moerman
Keyword(s):  
Carrier Mobility ◽  
Free Carrier ◽  
Dislocation Walls

ELECTRICAL AND OPTICAL PROPERTIES OF MULTILAYER SOL GEL ZnO COATINGS

2006 ◽  
Vol 20 (23) ◽  
pp. 3357-3364 ◽  
Author(s):  
TALAAT MOUSSA HAMMAD
Keyword(s):  
Carrier Mobility ◽  
Sol Gel ◽  
Dip Coating ◽  
Free Carrier ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Electrical And Optical Properties ◽  
Zinc Oxide Films ◽  
Free Carrier Density ◽  
Fine Microstructure

Multilayer transparent conducting zinc oxide films have been prepared on boro-silicate substrates by the commercially sol gel dip coating process. Each layer was fired at 550°C in a conventional furnace for 15 min. The final coatings were then tempered under a flux of forming gas ( N 2/ H 2) at 400°C for 2 h. The coatings were characterized by surface stylus profiling and optical spectroscopy (UV-NIR). Results show that (1) ZnO films with electrical resistivity of 6×10-4 Ω· cm , free carrier mobility of approximately 77 cm 2/ V · s and free carrier density of approximately 6.14×1019 cm -3 are obtained for multilayers 310 nm and (2) the transmittance is approximately 60.4% and the reflectance is nearly 34.7% are obtained at a wavelength of 800 nm when the thickness of the ZnO multilayers is 310 nm. The crystal structure and grain orientation of ZnO films were determined by X-ray diffraction. SEM investigations revealed that the surface morphology of growing ZnO films on boro-silicate substrate is dominated by the smooth surface with a fine microstructure.

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.

The intrinsic free carrier mobility in AlGaN/GaN quantum wells

2004 ◽  
Vol 831 ◽  
Author(s):  
F. Carosella ◽  
M. Germain ◽  
J.-L. Farvacque
Keyword(s):  
Quantum Wells ◽  
Carrier Mobility ◽  
Electron System ◽  
Relaxation Mechanism ◽  
Free Carrier ◽  
Free Carriers ◽  
Scattering Mechanisms ◽  
Carrier Interaction ◽  
Scattering Strength ◽  
Two Bodies

ABSTRACTThe aim of this contribution is to determine theoretically the maximum mobility that can be expected in AlGaN/GaN quantum wells as soon as the free carriers are only submitted to intrinsic scattering mechanisms associated with phonons and the carrier-carrier interaction. In our model, we consider that the carrier-carrier two bodies collisions do not constitute by themselves a relaxation mechanism since they conserve the momentum and the energy of the electron system. Thus, we assume that the free carriers act only through their contribution to the dynamical dielectric response of the material and, at least, through their collective behavior resulting into plasmons which, when damped, constitute now a real relaxation mechanism. The full scattering strength is connected with the imaginary part of the total reversed dielectric function including the lattice and the free carrier contributions. This approach automatically includes the scattering mechanisms associated with hybrid phonon/plasmon particles.

Phonons and Free Carriers in a Strained Hexagonal GaN-AlN Superlattice Measured by Infrared Ellipsometry and Raman Spectroscopy

1999 ◽  
Vol 595 ◽  
Author(s):  
M. Schubert ◽  
A. Kasic ◽  
T.E. Tiwald ◽  
J.A. Woollam ◽  
V. Harle ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Free Carrier ◽  
Phonon Modes ◽  
Lateral Mobility ◽  
Free Carriers ◽  
Organic Vapor ◽  
Infrared Ellipsometry ◽  
Order Of Magnitude ◽  
Metal Organic ◽  
Vertical Mobility

AbstractPhonon and free-carrier effects in a strained hexagonal (α) {GaN}l-{AlN}m superlattice (SL) heterostructure (l = 8 nm, m = 3 nm) are studied by infrared spectroscopic ellipsometry (IRSE) and micro (µ)-Raman scattering. Growth of the heterostructures was performed by metal-organic vapor phase epitaxy (MOVPE) on (0001) sapphire. An unstrained 1 µm-thick α-GaN layer was deposited prior to the SL. SL phonon modes are identified combining results from both IRSE and µ-Raman techniques. The shift of the GaN-sublayer phonon modes is used to estimate an average compressive SL stress of σxx ∼ - 4.3 GPa. The IRSE data reveal a free-carrier concentration of ne ∼ 5×1018 cm−3 within the undoped SL GaN-sublayers. According to the vertical carrier confinement, the free-carrier mobility is anisotropic, and the lateral mobility ( µ⊥ ∼ 400 cm2/Vs, polarization E⊥c-axis) exceeds the vertical mobility (µ∥ ∼ 24 cm2/Vs, E∥c) by one order of magnitude.

Free Carrier Mobility Extraction in FETs

2017 ◽  
Vol 64 (12) ◽  
pp. 5279-5283 ◽  
Author(s):  
Farzan Jazaeri ◽  
Alessandro Pezzotta ◽  
Christian Enz
Keyword(s):  
Carrier Mobility ◽  
Free Carrier

scholarly journals Far-infrared spectroscopy of PbTe doped with iron

2002 ◽  
Vol 67 (6) ◽  
pp. 415-423 ◽  
Author(s):  
Pantelija Nikolic ◽  
K. Radulovic ◽  
D. Vasiljevic-Radovic ◽  
V. Blagojevic ◽  
B. Milosavljevic ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Carrier Mobility ◽  
Hole Concentration ◽  
Far Infrared ◽  
Liquid Nitrogen Temperature ◽  
Free Carrier ◽  
Small Concentration ◽  
Far Infrared Spectroscopy ◽  
Infrared Reflection ◽  
Order Of Magnitude

Far infrared reflection spectra, at room and liquid nitrogen temperature, of PbTe single crystals doped with iron are presented. Plasma minima were observed at about 160 cm?1 and 180 cm?1 for room and liquid nitrogen temperature, respectively. Using the reflectivity diagrams and their minima the values of the hole concentrations and their mobility at both temperatures were calculated and compared with galvanomagnetic measurements. All these results indicated that when PbTe is doped with a small concentration of Fe, the hole concentration is reduced by one order of magnitude and the free carrier mobility is larger when compared to pure PbTe.

Structural and Electronic Properties of Laser Crystallized Silicon Films

1998 ◽  
Vol 536 ◽  
Author(s):  
T. Sameshima
Keyword(s):  
Energy Density ◽  
Hall Effect ◽  
Carrier Mobility ◽  
Laser Energy ◽  
Threshold Energy ◽  
Free Carrier ◽  
Silicon Films ◽  
Laser Energy Density ◽  
Threshold Energy Density ◽  
Hall Effect Measurements

AbstractFundamental properties of silicon films crystallized by a 30-ns-pulsed XeCI excimer laser were discussed. Although crystallization of 50-nm thick silicon films formed on quartz substrates occurred through laser hearing at the crystalline threshold energy density of 160 mJ/cm2, a higher laser energy density at 360 mJ/cm2 was necessary to crystallize silicon films completely. Analyses of free carrier optical absorption revealed that phosphorus-doped silicon films with a carrier density about 2×1020 cm−3 had a high carrier mobility of 20 cm2/Vs for irradiation at the crystallization threshold energy density, while Hall effect measurements gave a carrier mobility of electrical current traversing grain boundaries of 3 cm2/Vs. This suggested that the crystalline grains had good electrical properties. As the laser energy density increased to 360 mJ/cm2 and laser pulse number increased to 5, the carrier mobility obtained by the Hall effect measurements markedly increased to 28 cm2/Vs because of improvement of grain boundary properties, while the carrier mobility obtained by analysis of free carrier absorption increased to 40 cm2/Vs. A post annealing method at 190°C with high-pressure H2O vapor was developed to reduce the density of defect states. Increase of carrier mobility to 500 cm2/Vs was demonstrated in the polycrystalline silicon thin film transistors fabricated in laser crystallized silicon films.

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