• Electrical & Electronic Materials
• /
• v.9 no.6
• /
• pp.564-571
• /
• 1996

We calculated the drift-velocities of electrons and holes of I $n_{0.53}$(A $l_{x}$G $a_{1-x}$ )$_{0.47}$As, which is used for semiconductor materials of high performance HBTs, along with the various doping concentrations and Al mole fractions as well as the electric fields by Monte Carlo experiment. Especially, for the valence bands the accuracy of hole-drift-velocity was improved in the consideration of intervalley scattering due to the inelastic scattering of acoustic phonon. From the results the empirical formulas of the low- and high field mobility of electrons and holes were extracted by using nonlinear least square fitting method. The accuracy of the formulas was proved by comparing the formula of low-field electron mobility as well as drift-velocity of I $n_{0.53}$ G $a_{0.47}$As and of low-field hole mobility of GaAs with the measured values, where the error was below 10%. For the high-field mobilities of electron and hole the results calculated by the formulas were very well matched with the MC experimental results except at the narrow field range where the electrons produced the velocity overshoot and the corresponding error was about 30%.0%. 30%.0%.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.2
• /
• pp.52-55
• /
• 2006

The OLEDs(Organic Light-Emitting Diodes) structure organizes the bottom layer using glass, ITO(indium thin oxide), hole injection layer, hole transport layer, emitting material layer, electron transport layer, electron injection layer and cathode using metal. OLED has various advantages. OLEDs research has been divided into structural side and emitting material side. The amount of emitting light and luminescence efficiency has been improved by continuing effort for emitting material layer. The emitting light mechanism of OLEDs consists of electrons and holes injected from cathode and anode recombination in emitting material layer. The mobilities of injected electrons and holes are different. The mobility of holes is faster than that of electrons. In order to get high luminescence efficiency by recombine electrons and holes, the balance of their mobility must be set. The more complex thin film structure of OLED becomes, the more understanding about physical phenomenon in each interface is needed. This paper observed what the thickness change of hole transport layer has an affection through the below experiments. Moreover, this paper uses numerical analysis about carrier transport layer thickness change on the basis of these experimental results that agree with simulation results.

• The Korean Journal of Ceramics
• /
• v.6 no.2
• /
• pp.150-154
• /
• 2000

Mobilities of electrons ($\mu_p$) and holes ($\mu_p$) in 2, 5, and 10 mol% $TiO_2$-doped yttria stabilized zirconia (TD-YSZ) have been estimated by a non-steady state gas permeation method using models proposed by Weppner and Maruyama. Values of $\mu_n$ and $\mu_p$ were found to be closed to those in non-doped YSZ reported earlier. The concentration of electrons and holes were calculated from $\mu_n$ and $\mu_p$ values and the partial conductivities of electrons and holes measured by a dc-polarization method. The concentration of electrons at unit oxygen partial pressure increased with increasing $TiO_2$concentration, while the hole concentration was almost independent of $TiO_2$concentration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.8
• /
• pp.658-663
• /
• 2002

Hall factor of electrons in $\Gamma$-valley is calculated as functions of temperature, impurity concentration, and nonparabolicity of conduction valleys by taking into account the current density obtained from the Boltzmann transport equation. The dependence of the Hall factor on the temperature is clearly shown in the case of the optical phonon scattering and that on the impurity concentration is obvious in the case of the ionized impurity scattering. As the nonparabolicity of the conduction band increases, the Hall factor due to the acoustic or optic phonon scattering increases, whereas that due to the ionized impurity scattering decreases. The change of the Hall factor can be analysed in terms of the dispersion of relaxation time.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.3
• /
• pp.264-275
• /
• 2008

Electron mobility has been investigated theoretically in undoped double-gate (DG) MOSFETs of different channel architectures: a relaxed-Si DG SOI, a strained-Si (sSi) DG SSOI (strained-Si-on-insulator, containing no SiGe layer), and a strained-Si DG SGOI (strained-Si-on-SiGe-on-insulator, containing a SiGe layer) at 300K. Electron mobility in the DG SSOI device exhibits high enhancement relative to the DG SOI. In the DG SGOI devices the mobility is strongly suppressed by the confinement of electrons in much narrower strained-Si layers, as well as by the alloy scattering within the SiGe layer. As a consequence, in the DG SGOI devices with thinnest strained-Si layers the electron mobility may drop below the level of the relaxed DG SOI and the mobility enhancement expected from the strained-Si devices may be lost.

• Journal of information and communication convergence engineering
• /
• v.16 no.4
• /
• pp.248-251
• /
• 2018

To research the characteristics of $TiO_2$ as an insulator, $TiO_2$ films were prepared with various annealing temperatures. It was researched the currents of $TiO_2$ films with Schottky barriers in accordance with the contact's properties. The potential barrier depends on the Schottky barrier and the current decreases with increasing the potential barrier of $TiO_2$ thin film. The current of $TiO_2$ film annealed at $110^{\circ}C$ was the lowest and the carrier density was decreased and the resistivity was increased with increasing the hall mobility. The Schottky contact is an important factor to become semiconductor device, the potential barrier is proportional to the hall mobility, and the hall mobility increased with increasing the potential barrier and became more insulator properties. The reason of having the high mobility in the thin films in spite of the lowest carrier concentration is that the conduction mechanism in the thin films is due to the band-to-band tunneling phenomenon of electrons.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.1002-1006
• /
• 2004

The studies on OLED(Organic Light-Emitting Diode) materials and structures have been researched in other to improve luminescence efficiency of OLED. Electrons and holes are injected into the devices, transported across the layer and recombine to form excitons, their profiles are sensitive to mobility velocity of electrons and holes. A suggested means of improving the efficiency of LEDs would be to balance the injection of electrons and holes into light emission layer of the device. In this paper, we demonstrate the difference of velocity between hole and electron by experiments, and compare with a data of simulation and experiment changing hole carrier transport layer thickness, so we get the optimal we improve luminescence efficiency. We improve understanding of the various luminescence efficiency through experiments and numerical analysis of luminescence efficiency in the hole carrier transport layer's thicknes.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.408-408
• /
• 2014

Graphene has received attention with its high electron mobility and visual transparency as a promising material for optoelectronic and photonic applications. Combination of graphene and conducting nanostructures i.e. plasmonic structures has recently been researched for enhancing light-matter interaction and overcoming diffraction limit of light. Here we show enhanced photodetection of incoherent visible light with graphene-mediated plasmonics. Gold nanoparticles fabricated by focused ion beam was used as an active element of photodetection and graphene was utilized as an interfacing material between nanostructures and electrodes. Hot electrons generated upon plasmon decay within nanoparticles pass over the potential barrier between nanostructure and graphene and give rise to a photocurrent with built-in electric field. We report 76.7% enhancement of photocurrent under resonant irradiation of fiber-coupled halogen lamp compared to the case without light illumination. We showed wavelength-dependent current response arisen from plasmonic nanostructure, providing a good agreement with theoretical calculation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.04a
• /
• pp.85-88
• /
• 2006

The transport properties of amorphous selenium typical of the material used in direct conversion x-ray imaging devices are reported. The effects of As addition on the carrier mobility and recombination lifetime in amorphous selenium (a-Se) films have been studied using the moving photocarrier grating (MPG) technique. We have found an increase in hole drift mobility and recombination lifetime, especially when 0.3% As is added into a-Se film, whereas electron mobility decreases with As addition due to the defect density. The transport properties for As doped a-Se films obtained by using MPG technique have been compared with the drift mobilities of holes and electrons obtained by time of flight (TOF) measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.162-165
• /
• 2000

To investigate the effect of metal electrode in electroluminescent[EL] devices, we fabricated EL devices of ITO/P3HT/Al, ITO/P3HT/LiF/Al and ITO/P3HT/Mg:In structure. In current-voltage-light power characteristics, turn-on voltage of EL devices using LiF insulating layer and Mg:In(2.8V) metal electrode is lower than EL device using Al(4.2V). Besides the external quantum efficiency is improved also. The reason is related to carrier mobility and carrier injection, which would affect the hole-electron balance. In the device with Al electrode, holes injected from indium-tin-oxide[ITO] to poly(3-hexylthiophene)[P3HT] might reach the Al electrode without interacting with injected electrons, because the electron injection efficiency was very low for this electrode. Besides oxidation of the Al electrode is likely due to holes reaching the cathode without meeting injected electrons. Another possible reason for the higher EL efficiency may be the insulating layer playing the role of a tunneling barrier for holes to the Al electrode. In all EL devices, the orange-red light was clearly visible in a dark room. Maximum peak wavelength of EL spectrum emitted at 640nm in accordance with photon energy 1.9eV