scholarly journals Photo-excited charge carriers suppress sub-terahertz phonon mode in silicon at room temperature

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Bolin Liao ◽  
A. A. Maznev ◽  
Keith A. Nelson ◽  
Gang Chen
Keyword(s):  
Room Temperature ◽  
Phonon Mode ◽  
Charge Carriers

Laser Engineering of Barrier Structures Based on Solid Solution ZnCdHgTe.

2002 ◽  
Vol 719 ◽  
Author(s):  
Galina Khlyap
Keyword(s):  
Room Temperature ◽  
Film Surface ◽  
Charge Carriers ◽  
Barrier Structure ◽  
Free Charge ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Laser Engineering ◽  
Charged Defects ◽  
Epilayer Surface

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.

scholarly journals Ferromagnetic Behaviors in Fe-Doped NiO Nanofibers Synthesized by Electrospinning Method

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Yi-Dong Luo ◽  
Yuan-Hua Lin ◽  
Xuehui Zhang ◽  
Deping Liu ◽  
Yang Shen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Doping Concentration ◽  
Double Exchange ◽  
Host Lattice ◽  
Charge Carriers ◽  
Fe Doping ◽  
Free Charge ◽  
Ferromagnetic Properties ◽  
Electrospinning Method ◽  
Fe Ions

Ni1−xFexOnanofibers with different Fe doping concentration have been synthesized by electrospinning method. An analysis of the phase composition and microstructure shows that Fe doping has no influence on the crystal structure and morphology of NiO nanofibers, which reveals that the doped Fe ions have been incorporated into the NiO host lattice. Pure NiO without Fe doping is antiferromagnetic, yet all the Fe-doped NiO nanofiber samples show obvious room-temperature ferromagnetic properties. The saturation magnetization of the nanofibers can be enhanced with increasing Fe doping concentration, which can be ascribed to the double exchange mechanism through the doped Fe ions and free charge carriers. In addition, it was found that the diameter of nanofibers has significant impact on the ferromagnetic properties, which was discussed in detail.

scholarly journals Temperature Dependence of Hall Mobility AndCarrier Concentration of pb0.55S0.45 Films

2009 ◽  
Vol 6 (1) ◽  
pp. 129-134
Author(s):  
Baghdad Science Journal
Keyword(s):  
Hall Mobility ◽  
Room Temperature ◽  
Annealing Temperature ◽  
High Vacuum ◽  
Life Time ◽  
Mean Free Path ◽  
Charge Carriers ◽  
Evaporation Technique ◽  
Carrier Life Time ◽  
Type Conduction

Measurements of Hall effect properties at different of annealing temperature have been made on polycrystalline Pb0.55S0.45 films were prepared at room temperature by thermal evaporation technique under high vacuum 4*10-5 torr . The thickness of the film was 2?m .The carrier concentration (n) was observed to decrease with increasing the annealing temperature. The Hall measurements showed that the charge carriers are electrons (i.e n-type conduction). From the observed dependence on the temperature, it is found that the Hall mobility (µH), drift velocity ( d) carrier life time ( ), mean free path (?) were increased with increasing annealing temperature

scholarly journals Нерезонансное обращение волнового фронта света на поверхности пленок GaN при большой мощности оптического возбуждения

2019 ◽  
Vol 53 (1) ◽  
pp. 26
Author(s):  
А.Н. Грузинцев ◽  
А.Н. Редькин
Keyword(s):  
Photon Energy ◽  
Signal Intensity ◽  
Room Temperature ◽  
Phase Conjugation ◽  
Charge Carriers ◽  
Nitrogen Laser ◽  
Free Charge ◽  
Laser Pumping ◽  
Infrared Spectral ◽  
First Time

AbstractThe possibility of the nonresonance phase conjugation of light in an excited semiconductor medium is shown theoretically and experimentally. In epitaxial GaN films pumped with a nitrogen laser at room temperature, the induced phase conjugation of light in the visible and infrared spectral regions is detected for the first time. The dependences of the phase-conjugation signal intensity on the photon energy and laser-pumping intensity are studied. An interpretation of the effect as a result of the absorption and refraction of light at laser-induced free charge carriers in the semiconductor medium is proposed.

Manganese-Doped CdGeAs2, ZnGeAs2 and ZnSiAs2 Chalcopyrites: A New Advanced Materials for Spintronics

2010 ◽  
Vol 168-169 ◽  
pp. 31-34 ◽  
Author(s):  
A.S. Morozov ◽  
L.A. Koroleva ◽  
D.M. Zashchirinskii ◽  
T.M. Khapaeva ◽  
S.F. Marenkin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Charge Carriers ◽  
Advanced Materials ◽  
Temperature Dependences ◽  
P Type ◽  
Mn Doped ◽  
Curie Temperatures ◽  
Exchange And Superexchange Interactions

Based on the Mn-doped chalcopyrites CdGeAs2, ZnGeAs2 and ZnSiAs2, new dilute magnetic semiconductors with the p-type conductivity were produced. Magnetization, electrical resistivity and Hall effect of these compositions were studied. Their temperature dependences of magnetization are similar in form in spite of a complicated character, which is controlled by the concentration and mobility of the charge carriers. Thus, for T < 15 K, these curves are characteristic of superparamagnets and for T > 15 K, of a frustrated ferromagnet. In compounds with Zn these two states are diluted by a spinglass-like state. This specific feature is ascribed to attraction of Mn ions occupying neighboring sites and to competition between the carrier-mediated exchange and superexchange interactions. The Curie temperatures of these compounds are above room temperature. These are the highest Curie temperatures in the AIIBIVCV2:Mn systems.

scholarly journals Anisotropic ultrasensitive PdTe2-based phototransistor for room-temperature long-wavelength detection

2020 ◽  
Vol 6 (36) ◽  
pp. eabb6500
Author(s):  
Cheng Guo ◽  
Yibin Hu ◽  
Gang Chen ◽  
Dacheng Wei ◽  
Libo Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Mobility ◽  
Charge Carriers ◽  
Terahertz Frequency ◽  
Large Area ◽  
Long Wavelength ◽  
Terahertz Band ◽  
High Anisotropy ◽  
Topological Semimetals ◽  
Wavelength Detection

Emergent topological Dirac semimetals afford fresh pathways for optoelectronics, although device implementation has been elusive to date. Specifically, palladium ditelluride (PdTe2) combines the capabilities provided by its peculiar band structure, with topologically protected electronic states, with advantages related to the occurrence of high-mobility charge carriers and ambient stability. Here, we demonstrate large photogalvanic effects with high anisotropy at terahertz frequency in PdTe2-based devices. A responsivity of 10 A/W and a noise-equivalent power lower than 2 pW/Hz0.5 are achieved at room temperature, validating the suitability of PdTe2-based devices for applications in photosensing, polarization-sensitive detection, and large-area fast imaging. Our findings open opportunities for exploring uncooled and sensitive photoelectronic devices based on topological semimetals, especially in the highly pursuit terahertz band.

Bulk Modulus of the YBaCuO Oxide Superconductor Obtained from Magnetic Measurements

1989 ◽  
Vol 169 ◽  
Author(s):  
Bokhimi
Keyword(s):  
Magnetic Susceptibility ◽  
Bulk Modulus ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Oxygen Deficiency ◽  
External Pressure ◽  
Charge Carriers ◽  
Oxide Superconductor ◽  
Mechanical Measurements ◽  
Order Of Magnitude

AbstractStarting from the fact that the YBa2Cu3O7-x oxide superconductor system has a constant magnetic susceptibility at high temperatures for each oxygen deficiency x, and assuming that the charge carriers have a free-electron-like behavior, the observed magnetic susceptibility of the samples at room temperature can be associated to the Pauli paramagnetismus and to the Landau diamagnetism of the charge carriers. This result allows one to calculate the charge carriers density from the magnetic susceptibility in the sample. If besides one assume that by applying an external pressure on the sample, there is a change of the volume of the unit cell, but not in the number of the charge carriers in it, then, it is possible to calculate the Bulk modulus of the YBaCuO system at room temperature starting from these magnetic measurements. The obtained results are of the same order of magnitude to those reported in the literature and obtained from thermodynamic and mechanical measurements.

Charge Carrier Transport along Grain Boundaries in Silicon

2013 ◽  
Vol 205-206 ◽  
pp. 293-298 ◽  
Author(s):  
Martin Kittler ◽  
Manfred Reiche ◽  
Hans Michael Krause
Keyword(s):  
Charge Carrier ◽  
Grain Boundaries ◽  
Carrier Transport ◽  
Room Temperature ◽  
Drain Current ◽  
Charge Carriers ◽  
Strong Increase ◽  
Charge Carrier Transport ◽  
Mobility Of Charge Carriers

The influence of GBs contained in the channel of MOS-FETs - fabricated in thin SOI layers - is demonstrated. The drain current measured at room temperature increases about 50 times for nFETs and about 10 times for pFETs, respectively, as compared to reference devices. The observations might be interpreted as a strong increase of the mobility of charge carriers. Moreover, the observed stepwise changes of the drain current at 5 K may point to Coulomb blockades.

scholarly journals Graphene Schottky Junction on Pillar Patterned Silicon Substrate

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 659 ◽  
Author(s):  
Giuseppe Luongo ◽  
Alessandro Grillo ◽  
Filippo Giubileo ◽  
Laura Iemmo ◽  
Mindaugas Lukosius ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Room Temperature ◽  
Light Exposure ◽  
Photovoltaic Effect ◽  
Reverse Current ◽  
Charge Carriers ◽  
Graphene Monolayer ◽  
Temperature Dependent ◽  
Thermal Generation ◽  
Photo Response

A graphene/silicon junction with rectifying behaviour and remarkable photo-response was fabricated by transferring a graphene monolayer on a pillar-patterned Si substrate. The device forms a 0.11 eV Schottky barrier with 2.6 ideality factor at room temperature and exhibits strongly bias- and temperature-dependent reverse current. Below room temperature, the reverse current grows exponentially with the applied voltage because the pillar-enhanced electric field lowers the Schottky barrier. Conversely, at higher temperatures, the charge carrier thermal generation is dominant and the reverse current becomes weakly bias-dependent. A quasi-saturated reverse current is similarly observed at room temperature when the charge carriers are photogenerated under light exposure. The device shows photovoltaic effect with 0.7% power conversion efficiency and achieves 88 A/W photoresponsivity when used as photodetector.

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