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The radio frequency (RF) degradation mechanism under high temperature is proposed in this paper. The saturated output power (P sat), power added efficiency (PAE) and gain of the HEMTs deteriorate significantly under high power dissipation operation conditions, which contribute to an elevation of the junction temperature (T j). The high T j causes a negative shift of the threshold voltage and a reduction of electron mobility, as well as enhancing the trapping effects of the devices. As a result, the P sat and PAE of the high-power HEMTs (P sat = 152 W) decreased by 0.76 dB and 8.3%, respectively, which is more severe compared to low-power HEMTs (P sat = 20 W), where P sat and PAE reduced by 0.16 dB and 3.1% when the operation temperature was increased from 25 °C to 150 °C. By increasing the gate-to-drain distance from 1.625 to 2.175 μ m, drain current stability and high temperature reverse bias reliability are improved. The results demonstrate that the trapping effect can be suppressed by decreasing the electric field under the gate; therefore, the RF output characteristics are boosted by 1.2 W, 1 dB and 2.6% for a device with gate width of 11.52 mm. [ABSTRACT FROM AUTHOR]

The recombination dynamics are studied in viscous electron–hole plasma, consisting of electrons and photo-generated heavy and light holes, formed in the high-mobility mesoscopic GaAs channel. It is shown that an increase in the pump power reduces the concentration and mobility of background electrons, which, in turn, slows down their recombination with photogenerated holes. At a critical pump power, the recombination time begins to decrease, which is a consequence of the transition of a viscous electron–hole plasma from the hydrodynamic regime to the Drude diffusive regime. The observed transition occurs when the scattering of electrons with disorder begins to dominate over electron–electron scattering, which leads to the transformation of an inhomogeneous Poiseuille charge flow into a homogeneous diffusion flow. As a result, an optical analogue of the Gurzhi effect has been found. [ABSTRACT FROM AUTHOR]

This work is motivated by the recent fabrication of a new four-atom-thick hexagonal polymorph from group IV monochalcogenide, so-called γ -GeSe (Lee et al 2021 Nano Lett. 21 4305). In this paper, we propose and examine the structural characteristics, electronic properties, and carrier mobility of monolayers Janus γ -Ge2 XY ( X / Y = S, Se, or Te) based on comprehensive first-principles calculations. Monolayers γ -Ge2 XY are confirmed to be structurally stable. Our calculations reveal that γ -Ge2 XY monolayers are indirect semiconductors with Mexican-hat-like dispersions in the top valence band. While the effect of the electric field on the energy band dispersions of γ -Ge2 XY monolayers is weak, the energy band dispersions are changed drastically in the presence of strain, especially compressive strain. Interestingly, a structural phase transition from semiconductor to metal is observed in γ -Ge2 XY under compressive strain. γ -Ge2STe and γ -Ge2SeTe possess high electron mobility with values of 3.22 × 10 3 and 8.33 × 10 3 cm2 V−1 s−1, respectively. Our findings not only explore the fundamental physical properties of γ -Ge2 XY but also open up new opportunities in the design of high-performance electronic nanodevices based on layered nanomaterials with Mexican-hat-like dispersions. [ABSTRACT FROM AUTHOR]

In this paper, we systematically investigated the static properties and gate current mechanism of low-pressure chemical vapor deposition-SiN x /AlGaN/GaN metalâ€"insulatorâ€"semiconductor-high-electronmobility-transistor (MIS-HEMTs) at cryogenic temperature range from 10 K to 300 K. It is found that the threshold voltage of the device shows a positive shift due to the decreased carrier concentration at low temperature, and both the maximum transconductance and ON-resistance are improved at the low temperatures because of the enhanced electron mobility. Under very low electric field, the gate leakage exhibits ohmic conduction. With increasing forward gate bias, the dominant gate leakage mechanism at temperature below150 K gradually transits into trap-assisted tunneling, participating with a deep trap energy level of 0.73 eV in the SiN x dielectric, to Fowlerâ€"Nordheim (FN) tunneling. In contrast, the dominant gate leakage mechanism at temperature above 150 K transits from Pooleâ€"Frenkel emission, showing a low trap barrier height of 56 meV in the SiN x dielectric, to Fowlerâ€"FN tunneling with increasing forward gate bias. Under high reverse gate bias, carrier-limited gate current becomes the dominated gate leakage mechanism. [ABSTRACT FROM AUTHOR]

Charge transport behavior in SnO2 nanoparticle (NP) films is rather crucial to the optoelectronic devices. Temperature-dependent electrical results show that the electron transport in SnO2 NP films is dominated by the Mott variable-range hopping processes, i.e. the electrons are transported between different NPs through surface states rather than the conduction band of the nanocrystals, which is identical to the commonly used ZnO NP solids. Compared with ZnO, SnO2 films exhibit similar electron mobility but lower density of states (DOS). Therefore, we deduce that the low DOS in the SnO2 NP films should be the key factor limiting the device performance in compared with the ZnO as reported in most of the quantum-dot light-emitting diodes (QLEDs). Our work sheds light on optimizing SnO2 NP films for QLEDs. Moreover, we believe that the SnO2 remains a desirable candidate as the electron transport material for the QLEDs due to its excellent physicochemical stability. [ABSTRACT FROM AUTHOR]

Perovskite-based van der Waals heterostructures with high carrier mobility and perfect photoresponse performance can be used to design transistors and photovoltaic devices. However, the function of a single heterojunction is relatively limited because of its specific energy band type. To achieve more controllable device functions, in this work, the band structure, effective mass, optical absorption spectrum, differential charge density and other electronic and optical properties for the novel heterostructure system composed of emerging two-dimensional material Pd2Se3 with a high electron mobility and all-inorganic halide perovskite Cs2PbI2(1+x)Cl2(1−x) is systematically studied by using density functional theory. The results demonstrate that the band alignments in Cs2PbI2Cl2/Pd2Se3 heterostructure realize the transition from type-I to type-II by changing the concentration of I and Cl atoms in the all-inorganic two-dimensional Ruddlesen-Popper perovskite Cs2PbI2Cl2, which can be applied to different functional devices. With the increase of iodine atoms, the valence band maximum (VBM) contributed by Pd2Se3 in the heterostructure moves downward, and the valence band of Cs2PbI2Cl2 becomes the new VBM. Moreover, the transport and optical properties for the Cs2PbI2Cl2/Pd2Se3 heterostructure can be improved, due to the reductions in the band gap and effective mass, which are caused by the transition of band alignment. Our works indicate that a controllable band alignment of Cs2PbI2Cl2/Pd2Se3 heterostructure can provide theoretical guidance for the flexible designs of devices with multi-functional applications. [ABSTRACT FROM AUTHOR]

Layered molybdenum disulfide (MoS2) is emerging as a promising candidate for novel electronic applications, though the focus has largely been on few-layered thin films and in-layer electrical properties. MoS2 shows various nontrivial departures in its electrical properties in comparison to isotropic crystalline materials, however the understanding of anisotropic properties, particularly of charge carrier mobility in MoS2 flakes, is meagre. We experimentally study inter-layer mobility in mechanically exfoliated MoS2 flakes. The choice of a suitable sandwich device structure enables us to study the inter-layer transport using temperature dependent current–voltage (J–V) and impedance spectroscopy. The separation of peaks in the imaginary part of impedance i.e. Im (Z) spectra due to defects and transport in the space charge limited regime allows measurement of mobility un-encumbered by other effects. We study flakes obtained from both naturally occurring and synthetic crystals. The calculated inter-layer mobility () exhibits temperature dependence with δ = 1.6 and thereby revealing that impurity scattering is the dominant mechanism. A further confirmation that the mobility is limited by charged impurity scattering comes from the observation that it improves for temperatures lower than a characteristic temperature, which marks deionization of donor impurities. Our results provide a direct estimation of the inter-layer mobility in exfoliated MoS2 flakes and would lead to carrier transport engineering and design strategies for applications based on MoS2 flakes. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3), an emerging ultra-wide-bandgap semiconductor, has the desirable properties of a large bandgap of 4.6–4.9 eV, an estimated critical breakdown field of 8 MV cm−1, decent electron mobility of 250 cm2 V s−1 and high theoretical Baliga figures of merit (BFOMs) of around 3000. Bolstered by their capability of an economical growth technique for high-quality bulk substrate, β-Ga2O3-based materials and devices have been highly sought after in recent years for power electronics and solar-blind ultraviolet photodetectors. This article reviews the most recent advances in β-Ga2O3 power device technologies. It will begins with a summary of the field and underlying semiconductor properties of Ga2O3, followed by a review of the growth methods of high-quality β-Ga2O3 bulk substrates and epitaxial thin films. Then, brief perspectives on the advanced technologies and measurements in terms of ohmic contact and interface state are provided. Furthermore, some state-of-the-art β-Ga2O3 photoelectronic devices, power devices and radiofrequency devices with distinguished performance are fully described and discussed. Some solutions to alleviating challenging issues, including the difficulty in p-type doping, low thermal conductivity and low mobility, are also presented and explored. [ABSTRACT FROM AUTHOR]

The influence of chamber pressure and Si-doping on the growth rate, surface morphology and Hall mobility was investigated for β-Ga2O3 thin films homoepitaxially grown by metalorganic vapor phase epitaxy on Mg-doped β-Ga2O3 (100) substrates with 4° miscut. Transitions from step-bunching to step-flow to 2D island growth modes were achieved by varying the chamber pressure from 10 mbar to 40 mbar and/or by varying the O2/Ga ratio. High-quality β-Ga2O3 homoepitaxial thin films with a high electron mobility of 153 cm2 Vs−1 have been obtained at a chamber pressure of 25 mbar and a growth rate of 3.6 nm min−1. The Si-doped films show electron concentrations in the range of 1 × 1017 to 2 × 1019 cm−3. When increasing the chamber pressure to 40 mbar step-flow growth mode and high charge carrier mobility can only be preserved by adjusting the O2/Ga ratio and increasing the Ar push gas flow. Secondary ion mass spectrometry and Hall measurements for Si and electron concentration, respectively, revealed Si compensation at higher tetraethyl orthosilicate flux. [ABSTRACT FROM AUTHOR]

A flexible framework is obtained for enhancing both the thermal and electrical performance of fin field-effect transistor (FinFET) technology. Investigation of the nanoscale heat conduction within a short-channel field-effect transistor can be regarded as an emerging challenge related to future-generation transistors. In this work, we report the electrothermal transport in a 10 nm silicon-on-insulator (SOI) FinFET based on the dual-phase-lag model and modified drift-diffusion motions. We found that electron mobility decreases along the channel due to carrier confinement under higher electric field. In addition, the surface detection temperature indicates that the self-heating process is localized between the source and drain region. As promising results, high-κ metal-oxide and lower thermal boundary resistance can optimize the nanoscale heat transport in the SOI FinFET device. [ABSTRACT FROM AUTHOR]

Space charge formation in chromium-compensated GaAs sensors is investigated by the laser-induced transient current technique applying pulsed and DC bias. Formation of non-standard space charge manifested by an appearance of both negatively and positively charged regions in DC biased sensors was revealed during 5 ms after switching bias. Using Monte Carlo simulations of current transients we determined enhanced electron lifetime τ = 150 ns and electron drift mobility μd = 3650 cm2 Vs−1. We developed and successfully applied a theoretical model based on fast hole trapping in the system with spatially variable hole conductivity. [ABSTRACT FROM AUTHOR]

Due to the large surface to volume ratio of two-dimensional (2D) materials, the electrical performance of MoS2 is very sensitive to extrinsic ambient conditions. Post treatments are favorable to improve or recover the electrical performance of MoS2. In this work, the influence of post forming gas annealing (FGA) and bis(trifluoromethane) sulfonamide (TFSI) treatment on the electrical performance of monolayer top-gated MoS2 transistors is investigated. A negative shift of threshold voltage and an improvement in electron mobility are observed for both the post FGA and TFSI treatment. However, post TFSI treatment is more effective than the post FGA treatment in improving the electron mobility and gate controllability. Linear transmission-line-model measurement results indicate that the post FGA treatment is preferable in reducing the contact resistance, while post TFSI treatment is more effective in reducing the sheet resistance of MoS2. Raman and x-ray photoelectron spectroscopy reveal that water desorbs from MoS2 after the FGA and TFSI treatment and S vacancies are introduced into MoS2 after FGA. The results show that post TFSI treatment can be a simple and effective approach to improve the electrical property of MoS2 and may be used for other S-containing 2D transition metal dichalcogenides. [ABSTRACT FROM AUTHOR]

The ideal electron transport layer of a high performance perovskite solar cell should have good optical transparency, high electron mobility, and an energy level alignment well-matched with the perovskite material. In this work, we investigate the role of TiCl4 post-treatment of the mesoporous TiO2 electron transport layer by varying the concentration of TiCl4 and characterizing optical and electrical properties, charge carrier dynamics, and photovoltaic performance of mesoscopic CH3NH3PbI3 solar cells. It is found that the TiCl4 treatment provides an additional interconnection between the TiO2 particles, leading to better percolation as evident from high resolution cross-section images and chemical maps. This enhances effective electron mobility in the material as well as significantly reduces average sub-bandgap absorption due to defects and electronic disorder determined by photothermal deflection spectroscopy. Moreover, improvement of interfacial contact due to a smoother surface contributes to more efficient charge extraction and suppressed charge recombination and reduced hysteresis. As a result, the optimized device based on TiCl4 post-treated mesoporous TiO2 achieved the highest conversion efficiency of 17.4% compared with 14.1% for the device with pristine mesoporous TiO2. [ABSTRACT FROM AUTHOR]

Smooth interfaces and surfaces are beneficial for most (opto)electronic devices that are based on thin films and their heterostructures. For example, smoother interfaces in (010) β-Ga2O3/(AlxGa1-x)2O3 heterostructures, whose roughness is ruled by that of the β-Ga2O3 layer, can enable higher mobility 2-dimensional electron gases by reducing interface roughness scattering. To this end we experimentally prove that a substrate offcut along the [001] direction allows to obtain smooth β-Ga2O3 layers in (010)-homoepitaxy under metal-rich deposition conditions. Applying In-mediated metal-exchange catalysis (MEXCAT) in molecular beam epitaxy at high substrate temperatures (Tg = 900 °C) we compare the morphology of layers grown on (010)-oriented substrates having different unintentional offcuts. The layer roughness is generally ruled by (i) the presence of (110)- and -facets visible as elongated features along the [001] direction (rms < 0.5 nm), and (ii) the presence of trenches (5–10 nm deep) orthogonal to [001]. We show that an unintentional substrate offcut of only ≈ 0.1° almost oriented along the [001] direction suppresses these trenches resulting in a smooth morphology with a roughness exclusively determined by the facets, i.e. rms ≈ 0.2 nm. Since we found the facet-and-trench morphology in layer grown by MBE with and without MEXCAT, we propose that the general growth mechanism for (010)-homoepitaxy is ruled by island growth whose coalescence results in the formation of the trenches. The presence of a substrate offcut in the [001] direction can allow for step-flow growth or island nucleation at the step edges, which prevents the formation of trenches. Moreover, we give experimental evidence for a decreasing surface diffusion length or increasing nucleation density on the substrate surface with decreasing metal-to-oxygen flux ratio. Based on our experimental results we can rule-out step bunching as cause of the trench formation as well as a surfactant-effect of indium during MEXCAT. [ABSTRACT FROM AUTHOR]

Because of the relatively low electron mobility of Ga2O3, it is important to identify suitable current spreading materials. Fluorine-doped SnO2 (FTO) offers superior properties to those of indium tin oxide (ITO), including higher thermal stability, a larger bandgap, and lower cost. However, the Ga2O3:Si/FTO heterojunction, including the important band offsets and the I–V characteristics, have not previously been reported. In this work, we have grown a Ga2O3:Si/FTO heterojunction and performed x-ray photoelectron spectroscopy measurements. The conduction and valence band offsets were determined to be 0.11 and 0.42 eV, indicating a minor barrier for electron transport and a type-I heterojunction. The subsequent I–V measurement of the Ga2O3:Si/FTO heterojunction exhibited pseudo-ohmic behavior. The results of this work support the potential of FTO for the current spreading layers of Ga2O3 devices for high temperature and ultraviolet applications. [ABSTRACT FROM AUTHOR]

Two-dimensional polyaniline monolayers (C3N) have been recently synthesized as indirect semiconductors with high electron mobility. We investigate the electrical and thermal properties of a C3N sheet using a combination of density functional theory and the Green function formalism. Tensile strain along a zigzag direction can drive the transition from an indirect to a direct semiconductor, whereas the sheet transitions from a semiconductor to a metal under compressive strain. The thermoelectric efficiency of an unstrained C3N sheet is higher in p-doping, and its maximum value is obtained when the transport is along the zigzag direction. A reduction in the figure of merit is found upon applying strain, independent of its direction. To overcome this reduction, we show that when the electrical transport and strain are perpendicular to each other, the thermoelectric efficiency of the C3N sheet can be significantly increased, depending on the type of strain (tensile or compression). The results support the potential application of C3N sheets in the thermoelectrics and optoelectronics industries through using strain engineering. [ABSTRACT FROM AUTHOR]

Through first-principle calculations, we investigate the stability, electronic structures, elasticity, piezoelectricity, and mobility of 2D BiTeI monolayer. Our calculations show that 2D BiTeI monolayer is energetically, mechanically, thermodynamically, and dynamically stable. In addition to its well-known large Rashba spin-splitting, the monolayer exhibits a high-tensile ductility and mechanical flexibility. Formation of BiTeI/BN van der Waals heterostructure makes it freestanding without perturbing the electronic structure. The broken mirror symmetry structure induces out-of-plane internal electric field of 0.289 eV Ĺ−1, yielding out-of-plane piezoelectric coefficients of 0.556 pm V−1, which is larger than that of Janus group III and transition metal chalcogenide monolayers. Furthermore, the effective masses and mobility of electrons are 0.176 me and 392 cm2 V–1 s–1, respectively, which are half and six times of those of the MoS2 monolayer, respectively. These charateristics make 2D BiTeI a potential candidate for a wide variety of applications in nanoscale spin and electromechanical devices. [ABSTRACT FROM AUTHOR]

Indium tin oxide (ITO) has a wide range of applications at its epsilon-near-zero (ENZ) wavelength due to its unique optical properties. Post-annealing is a simple way to tune the ENZ wavelength. We show that the ENZ wavelength of ITO films could be red-shifted over a wide range from 1200 nm to 1550 nm by thermal annealing in air for durations up to 130 min at 330 °. Optical transmittance and reflectance spectra were measured for these ITO samples, along with electron densities, to extract the Drude model parameters of plasma frequency, damping factor, electron mobility and effective mass. The results show that the changes in electron density and effective mass collectively cause the red-shift in the plasma frequency and ENZ wavelength. The oxygen uptake and crystallite size increase during the annealing in the air are the main reasons for the change in electronic properties. This versatile method of tuning the ITO's ENZ wavelength can expand the wavelength range for applications and adapt it to working at wavelengths of plasmonic devices in the telecommunication wavebands. [ABSTRACT FROM AUTHOR]

The lateral and in-depth metal segregation of Au/Ni/Al/Ti ohmic contacts for GaN-based high electron mobility transistors were analysed as a function of the Al barrier's thickness (d). The surface of the contacts, characterized by atomic force and scanning electron microscopy, shows a transition from a fractal network of rough and complex island-like structures towards smoother and cauliflower-like fronts with increasing d. Rutherford backscattering spectrometry and energy dispersive x-ray spectroscopy (EDXS) at different energies were used to confirm the in-depth intermixing of the metals relevant for the final contact resistance. EDXS mapping reveals a significant lateral segregation too, where the resulting patterns depend on two competing NiAlx and AuAlx phases, the intermixing being controlled by the available amount of Al. The optimum ohmic resistance is not affected by the patterning process, but is mainly dependent on the partial interdiffusion of the metals. [ABSTRACT FROM AUTHOR]

Graphene nanoribbon (GNR) is a recently discovered carbon allotrope, which can be described as a stripe of graphene. Pseudo-one-dimensionality exerts additional confinement on the electrons resulting in the formation of a band gap relevant for electronic devices. Due to distinct physical and chemical properties it is a promising material for several applications. To expand the range of potential applications and to improve processability, chemical functionalization of GNRs is required. This review aims to provide a concise and systematic coverage of recent work in chemical functionalization of GNRs. We will focus on longitudinal carbon nanotube unzipping, functionalization with aryl diazonium salts, non-covalent functionalization, bottom-up synthesis and one pot carbon nanotube unzipping with in situ edge functionalization. [ABSTRACT FROM AUTHOR]

This paper describes a hybrid algorithm to study the effect of a gaseous void on bipolar charge transport in layered polymer film. This hybrid algorithm uses a source distribution technique based on an axisymmetric boundary integral equation method to solve the Poisson equation and a fourth order Runge–Kutta (RK4) method with an upwind scheme for time integration. Iterative stability is assured by satisfying the Courant–Friedrichs–Levy stability criterion. Dynamic charge mapping is achieved by allowing conducting and insulating boundaries and material interfaces to be represented by equivalent free and bound charge distributions that collectively satisfy all local and far-field conditions. This hybrid technique caters to bipolar charge injection, field-dependent mobility transport, recombination, and trapping/de-trapping in the bulk and at material and physical interfaces. The resulting charge map is the taxonomy of the different charge types and their abundance, and presents a dynamic view of the temporal and spatial distributions. The paper is motivated by images of breakdown experiments that point to the role of gaseous void in delamination growth. For the test configuration, the high field at the edge of the gaseous void act as a sink first for positive and then negative charge. The net effect is to increase delamination stress at the edge leading to further growth of the defect and increasing the potential for partial discharge within the void. [ABSTRACT FROM AUTHOR]

Fluorine doped SnO2 (FTO) nanobelts were synthesized and their transport properties, such as conduction mechanism, mobility, carrier density and density of states (DOS) were investigated. Variable range hopping was observed as the dominant mechanism in a large range of temperature (40–260 K). Through these data we estimated the localization length and hopping distance at 300 K of FTO nanobelts exhibiting a three-dimensional character for carrier transport. The carrier mobility was calculated to be 48 cm2 V−1 s−1 for samples with carrier density of 2 × 1018 cm−3. Taking into account the parameters obtained from temperature-dependent resistivity and the above data, the characteristic DOS at Fermi level in our samples was found. [ABSTRACT FROM AUTHOR]

ZnO and related alloys are an important class of materials to realize transparent electronics because of their characteristic wide band-gap and high mobility, and also because of their practical advantages, such as: available n-type materials and bulk single crystals, low-cost production, and absence of toxicity. Our studies have been conducted for more than a decade and they have enabled surface and interface engineering on an atomic scale, presenting a promising technology for developing electrical devices of various kinds. The quality of the epitaxial films was improved drastically when grown on high-temperature annealed buffer layers prepared on lattice-matched ScAlMgO4 substrates using pulsed-laser deposition. We carefully investigated the growth temperature dependence of surface morphology and electrical properties. Electron mobility was recorded as 440 cm2 V−1 s−1 at room temperature and 5500 cm2 V−1 s−1 at 1 K, leading to observation of the integer quantum Hall-effect (QHE) in abrupt ZnO/MgxZn1−xO interfaces. Two-dimensional electron gas (2DEG) was formed spontaneously in the interface because of the polarization mismatch between the layers. The observation of QHE enables us to access the direct determination of the interfacial electronic structure. In addition, the field-effect control of 2DEG has been demonstrated using lattice-matched interfaces as high-mobility channels. [ABSTRACT FROM AUTHOR]

The effect of Al2O3 mixing in HfO2 on the electrical properties was studied on InP substrates using nanolaminate films grown by atomic layer deposition. The In out-diffusion and the subsequent In-related oxide phase generation were effectively suppressed by introducing more Al2O3 to the HfO2 film. Although the decrease in the maximum capacitance was taken into consideration, more Al2O3 introduction significantly improved the dielectric properties. The magnitude of the capacitance–voltage frequency dispersion was decreased with the reduced border trap and interface state densities. Additionally, the leakage current characteristics were improved, including the voltage-stress-dependent reliability. [ABSTRACT FROM AUTHOR]

The effects of solvent and thermal annealing on the morphology of the active layers and the photovoltaic performance of bulk-heterojunction (BHJ) polymer solar cells (PSCs) are investigated systematically, for PSCs based on a blend of poly(3-hexylthiophene) (P3HT) as a donor and indene-C70 bisadduct (IC70BA) as an acceptor. IC70BA crystallites are found reasonably well dispersed in the P3HT matrix after spin-coating. However, the IC70BA crystallites coarsen in size after annealing, which are clearly evidenced by transmission electron microscopy. Simultaneously, space charge limited current measurements demonstrate that solvent and thermal annealing can improve the hole and electron mobility, which reduces charge-carrier recombination and improves charge-carrier transport in the P3HT and IC70BA blend layers. The corresponding current-voltage curves are measured in quantity and we propose a model to show the variation of the ordered structure of P3HT domains and IC70BA crystallite characteristics in the phase separation process, expressing a viewpoint on the high performance of BHJ PSCs. [ABSTRACT FROM AUTHOR]

The study of electron mobility of bis(2-methyl 8-hydroxyquinoline) (triphenyl siloxy) aluminium (SAlq) by transient electroluminescence (EL) is presented. An EL device is fabricated in bilayer, ITO/N,N'-diphenyl-N, N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD)/SAlq/LiF/Al configuration. The temporal evaluation of the EL with respect to the step voltage pulse is characterized by a delay time followed by a fast initial rise, which is followed by a slower rise. The delay time between the applied electrical pulse and the onset of EL is correlated with the carrier mobility (electron in our case). Transient EL studies for SAlq have been carried out at different temperatures and different applied electric fields. The electron mobility in SAlq is found to be field and temperature dependent and calculated to be 6.9 × 10[?]7 cm2 V[?]1 s[?]1 at 2.5 × 106 V cm[?]1 and 308 K. The EL decays immediately as the voltage is turned off and does not depend on the amplitude of the applied voltage pulse or dc offset. [ABSTRACT FROM AUTHOR]

A new zinc-blende type photoelectronic single crystal, Hg(3[?]3x)In2xTe3 (MIT), was grown by using the vertical Bridgman method. The structure of the MIT (x = 0.5) crystal was examined by x-ray powder diffraction. The lattice parameters were determined to be 6.2934 +- 0.0011 with a defect zinc-blende structure, which belongs to the group {F} \bar{4}3m . The melting point of the MIT crystal was measured by using the differential scanning calorimetry. Hall effect measurements on electrical properties at room temperature show that resistivity, carrier density and mobility of MIT crystal were 4.79 x 102 O cm, 2.83 x 1013 cm[?]3 and 4.60 x 102 cm2 V[?]1 s[?]1, respectively. The electron effective mass at the bottom of the conduction band and the top of the valence band was calculated. It was found that the Fermi level of the MIT crystal was about 0.008 eV higher than that of the mid-gap. The experimental carrier concentration was in good accordance with the theoretical result. [ABSTRACT FROM AUTHOR]