Carrier Transport and Luminescence Properties of Nanocomposites of Poly[2-methoxy-5-(2-ethyl hexyloxy)-p-phenylene vinylene] and Dehydrated Nanotubes Titanic Acid

2007 ◽  
Vol 7 (12) ◽  
pp. 4318-4321
Author(s):  
Ting Zhang ◽  
Zheng Xu ◽  
Ran Liu ◽  
Feng Teng ◽  
Yongsheng Wang ◽  
...  
Keyword(s):  
Outer Surface ◽  
Quantum Confinement ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Phenylene Vinylene ◽  
Antenna Effect ◽  
Recombination Efficiency ◽  
Luminescence Efficiency ◽  
Exciton Recombination ◽  
Interchain Interactions

The carrier transport capability and luminescence efficiency of poly(2-methoxy-5-(2-ethyl hexyloxy)-p-phenylene vinylene) (MEH-PPV) films are enhanced by doping with dehydrated nanotubed titanic acid (DNTA). MEH-PPV molecules, either wrapped on the outer surface of or encapsulated into DNTA pores, have a more open, straighter conformation than undoped molecules, which induces a longer conjugated backbone and stronger interchain interactions, thereby, enhancing carrier mobility. MEH-PPV molecules within DNTA pores have higher exciton recombination efficiency owing to quantum confinement and the antenna effect.

scholarly journals Universal mobility characteristics of graphene originating from charge scattering by ionised impurities

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jonathan H. Gosling ◽  
Oleg Makarovsky ◽  
Feiran Wang ◽  
Nathan D. Cottam ◽  
Mark T. Greenaway ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carrier Density ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Analytical Models ◽  
Pristine Graphene ◽  
High Electron ◽  
Boltzmann Transport ◽  
Transport Parameters ◽  
Wide Range

AbstractPristine graphene and graphene-based heterostructures can exhibit exceptionally high electron mobility if their surface contains few electron-scattering impurities. Mobility directly influences electrical conductivity and its dependence on the carrier density. But linking these key transport parameters remains a challenging task for both theorists and experimentalists. Here, we report numerical and analytical models of carrier transport in graphene, which reveal a universal connection between graphene’s carrier mobility and the variation of its electrical conductivity with carrier density. Our model of graphene conductivity is based on a convolution of carrier density and its uncertainty, which is verified by numerical solution of the Boltzmann transport equation including the effects of charged impurity scattering and optical phonons on the carrier mobility. This model reproduces, explains, and unifies experimental mobility and conductivity data from a wide range of samples and provides a way to predict a priori all key transport parameters of graphene devices. Our results open a route for controlling the transport properties of graphene by doping and for engineering the properties of 2D materials and heterostructures.

Time-resolved Photoconductivity as a Probe of Carrier Transport in Microcrystalline Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Steve Reynolds
Keyword(s):  
Density Of States ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Film Growth ◽  
Hole Mobility ◽  
Transport Parameters ◽  
Microcrystalline Silicon ◽  
Time Resolved ◽  
Transient Photoconductivity ◽  
Transport Measurements

AbstractThe use of transient photoconductivity techniques in the investigation of carrier transport in microcrystalline silicon is described. Results are presented which highlight variations in transport parameters such as carrier mobility and density of states with structure composition. Hole mobility is significantly enhanced by crystalline content in the film of 10% or less. The density of states inferred from transport measurements parallel to and at right angles to the direction of film growth differ somewhat, suggesting that transport may be anisotropic.

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.

scholarly journals Remote Phonon Scattering in Two-Dimensional InSe FETs with High-κ Gate Stack

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 674 ◽  
Author(s):  
Pengying Chang ◽  
Xiaoyan Liu ◽  
Fei Liu ◽  
Gang Du
Keyword(s):  
Quantum Confinement ◽  
Carrier Mobility ◽  
Gate Dielectric ◽  
Phonon Scattering ◽  
Field Effect Transistors ◽  
Temperature Inversion ◽  
Two Dimensional ◽  
Mass Approximation ◽  
Mobility Degradation ◽  
Dual Gate

This work focuses on the effect of remote phonon arising from the substrate and high-κ gate dielectric on electron mobility in two-dimensional (2D) InSe field-effect transistors (FETs). The electrostatic characteristic under quantum confinement is derived by self-consistently solving the Poisson and Schrödinger equations using the effective mass approximation. Then mobility is calculated by the Kubo–Greenwood formula accounting for the remote phonon scattering (RPS) as well as the intrinsic phonon scatterings, including the acoustic phonon, homopolar phonon, optical phonon scatterings, and Fröhlich interaction. Using the above method, the mobility degradation due to remote phonon is comprehensively explored in single- and dual-gate InSe FETs utilizing SiO2, Al2O3, and HfO2 as gate dielectric respectively. We unveil the origin of temperature, inversion density, and thickness dependence of carrier mobility. Simulations indicate that remote phonon and Fröhlich interaction plays a comparatively major role in determining the electron transport in InSe. Mobility is more severely degraded by remote phonon of HfO2 dielectric than Al2O3 and SiO2 dielectric, which can be effectively insulated by introducing a SiO2 interfacial layer between the high-κ dielectric and InSe. Due to its smaller in-plane and quantization effective masses, mobility begins to increase at higher density as carriers become degenerate, and mobility degradation with a reduced layer number is much stronger in InSe compared with MoS2.

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO4, CuO, and WO3 Thin Films for Photoelectrocatalysis

2020 ◽  
Vol 234 (4) ◽  
pp. 699-717
Author(s):  
James Hirst ◽  
Sönke Müller ◽  
Daniel Peeters ◽  
Alexander Sadlo ◽  
Lukas Mai ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Terahertz Spectroscopy ◽  
Chemical Vapor ◽  
Photoelectrochemical Cells ◽  
Time Resolved ◽  
And Diffusion ◽  
Wo3 Thin Films ◽  
Carrier Transport Properties

AbstractThe temporal evolution of photogenerated carriers in CuWO4, CuO and WO3 thin films deposited via a direct chemical vapor deposition approach was studied using time-resolved microwave conductivity and terahertz spectroscopy to obtain the photocarrier lifetime, mobility and diffusion length. The carrier transport properties of the films prepared by varying the copper-to-tungsten stoichiometry were compared and the results related to the performance of the compositions built into respective photoelectrochemical cells. Superior carrier mobility was observed for CuWO4 under frontside illumination.

scholarly journals Coulomb drag transistor using a graphene and MoS2 heterostructure

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Youngjo Jin ◽  
Min-Kyu Joo ◽  
Byoung Hee Moon ◽  
Hyun Kim ◽  
Sanghyup Lee ◽  
...  
Keyword(s):  
High Performance ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Passive Layer ◽  
Strong Interactions ◽  
Practical Application ◽  
Coulomb Drag ◽  
Strong Coulomb ◽  
High Carrier Mobility ◽  
High Carrier

Abstract Two-dimensional (2D) heterostructures often provide extraordinary carrier transport as exemplified by superconductivity or excitonic superfluidity. Recently, a double-layer graphene (Gr) separated by few-layered boron nitride demonstrated the Coulomb drag phenomenon: carriers in the active layer drag carriers in the passive layer. Here, we propose high-performance Gr/MoS2 heterostructure transistors operating via Coulomb drag, exhibiting a high carrier mobility (∼3700 cm2 V−1 s−1) and on/off-current ratio (∼108) at room temperature. The van der Waals gap at the Gr/MoS2 interface induces strong interactions between the interlayer carriers, whose recombination is suppressed by the Schottky barrier between p-Gr and n-MoS2, clearly distinct from the presence of insulating layers. The sign reversal of lateral voltage clearly demonstrates the Coulomb drag in carrier transport. Hole-like behavior of electrons in the n-MoS2 is observed in magnetic field, indicating strong Coulomb drag at low temperature. Our Coulomb drag transistor thus provides a shortcut for the practical application of 2D heterostructures.

Field Effect Mobility of F16PcCu Films in Various Gas Atmospheres

1999 ◽  
Vol 03 (07) ◽  
pp. 667-671 ◽  
Author(s):  
HIROKAZU TADA ◽  
HIROSHI TOUDA ◽  
MASAKI TAKADA ◽  
KAZUMI MATSUSHIGE
Keyword(s):  
Carrier Density ◽  
Field Effect ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Room Temperature ◽  
Gas Adsorption ◽  
Quick Recovery ◽  
Thermally Activated ◽  
High Carrier ◽  
Gas Molecules

The electron mobility of hexadecafluorophthalocyaninato-copper ( F 16 PcCu ) films was evaluated based on field effect measurements in vacuum and in various gas atmospheres. An Arrhenius plot of the mobility showed that the carrier transport followed a thermally activated hopping mechanism with an activation energy of 0.28 eV. The mobility evaluated for freshly prepared films in ultrahigh vacuum was 2.0 × 10−3 cm 2 V −1 s −1 at room temperature. The electrical conductivity and carrier density were 4.4 × 10−5 S cm −1 and 1.4 × 1017 cm −3 respectively. The high carrier density indicated the existence of impurities acting as electron donors in the films. The field effect carrier mobility increased to 5.7 × 10−3 cm 2 V −1 s −1 in NH 3 atmosphere (100%, 1 atm) and decreased by 75% in the presence of O 2 gas (100%, 1 atm). A quick recovery of mobility was observed when the gas molecules were evacuated, indicating a low capability of gas adsorption.

Resonant excitation of Er3+ by the energy transfer from Si nanocrystals

2000 ◽  
Vol 638 ◽  
Author(s):  
Kei Watanabe ◽  
Minoru Fujii ◽  
Shinji Hayashi
Keyword(s):  
Energy Transfer ◽  
Transfer Process ◽  
Quantum Confinement ◽  
Energy Transfer Process ◽  
Exciton Energy ◽  
Si Nanocrystals ◽  
Wide Range ◽  
Exciton Recombination ◽  
Average Size ◽  
Co Doped

AbstractPhotoluminescence (PL) of SiO2 films co-doped with Si nanocrystals (nc-Si) and Er was studied. The average size of nc-Si was changed in a wide range in order to tune the exciton energy of nc-Si to the energy separations between the discrete electronic states of Er3+. PL from exciton recombination in nc-Si and the intra-4f shell transition of Er3+ were observed simultaneously. At low temperatures, periodic features were observed in the PL spectrum of nc-Si. The period agreed well with the optical phonon energy of Si. The appearance of the phonon structures implies that nc-Si which satisfy the energy conservation rule during the energy transfer process can resonantly excite Er3+. The effects of the quantum confinement of excitons in nc-Si on the energy transfer process are discussed.

Sign in / Sign up

Export Citation Format

Share Document