Electrical Transport Mechanism Research Articles

Electrical transport and dielectric relaxation mechanism in Zn0.5Cd0.5Fe2O4 spinel ferrite: A temperature- and frequency-dependent complex impedance study

In the present study, the frequency-dependent dielectric relaxation and electrical conduction mechanisms in sol-gel-derived Zn0.5Cd0.5Fe2O4 (ZCFO) spinel ferrite were studied in the temperature range of 343–438 K. The formation of the ZCFO spinel ferrite phase with space group Fd3m was confirmed by X-ray diffraction analysis. The dielectric relaxation and electrical conduction mechanisms were studied using complex impedance spectroscopy (CIS). In the Nyquist plots, depressed semicircles were fitted with an equivalent circuit model with configuration (RGBQGB) (RGQG), signifying the contributions from grain boundaries and grains to the charge transport mechanism in the sample. The frequency-dependent AC conductivity was found to follow Jonscher's power law, and the frequency exponent term depicted the overlapping large polaron hopping (OLPH) model as the dominant transport mechanism. The activation energies for conductivity, electric modulus and impedance were calculated to identify the nature of the charge carriers governing the relaxation and conduction mechanisms in the prepared sample. Complex modulus studies confirmed the non-Debye type of dielectric relaxation, whereas tangent loss and dielectric constant analyses confirmed the thermally activated hopping mechanism of charge carriers in Zn0.5Cd0.5Fe2O4 spinel ferrite.

Role of Ti interfacial layer in the stability of TiO2 based transparent synaptic device

Interface engineering plays a pivotal role in manipulating the electrical transport and conduction mechanism of a synaptic device. In this work, the impact of Ti as an interfacial layer is systematically investigated by inserting ∼5 nm thin film at both interfaces of a functional layer (TiO2). Interestingly, it was observed that Ti layers significantly regulate the migration of oxygen ions/vacancies at the interfaces yielding an improved stability from 10 to 200 cycles, sustained over a longer period ∼8 × 103 s. Forming free and gradual transition in conductance on positive bias region under a controlled compliance current ∼0.3–17 mA demonstrates the multilevel switching highlighting the typical synaptic behavior of memristor. The ohmic conduction and space charge-limited current mechanism was found across the various resistive states signifies the trapping/de-trapping. Besides, other key parameters of synaptic device such as paired pulse facilitation, depression, and short-term memory together with the excellent transmittance in the visible spectral range makes our device adequate for innovative transparent neuromorphic applications.

Experimental and Didactical Strategy to Improve Understanding of the Fundamental Concepts in Quantum Physics.

Quantum physics is an essential theory serving to explore nature at its smallest scales. Interaction between elemental particles in matter is leading toward new potential alternatives for producing decarbonized clean energies. Despite its importance, students find difficulties in understanding quantum mechanics due to a wrong categorization of the fundamental concepts. Studying quantum physics needs a new flexible ontology in which the quantum entity can have particle or wave properties depending on the context. We developed a workshop in quantum devices to put concepts into the correct conceptual categorization. With the aim of strengthening interinstitutional exchange, we realized the workshop with a population conformed by environmental engineering students of the Corporación Universitaria Uniagraria. Meeting took place in the Institución Universitaria Politécnico Grancolombiano facilities. Laser, LED (Light Emitting Diode), and photocell were the devices used to introduce the most fundamental concepts of quantum physics. The theoretical component of the workshop was divided into two main elements, the first, radiation-matter interaction, and the second, electrical transport mechanisms in materials. Pedagogical instruments employed were diagnostic proof, evaluative proof, and satisfaction inquiry. Despite the success achieved in the general realization of the workshop, students suggested some aspects for considering in future versions.

Exploring the Effect of V2O5 and Nb2O5 Content on the Structural, Thermal, and Electrical Characteristics of Sodium Phosphate Glasses and Glass-Ceramics.

Na-V-P-Nb-based materials have gained substantial recognition as cathode materials in high-rate sodium-ion batteries due to their unique properties and compositions, comprising both alkali and transition metal ions, which allow them to exhibit a mixed ionic-polaronic conduction mechanism. In this study, the impact of introducing two transition metal oxides, V2O5 and Nb2O5, on the thermal, (micro)structural, and electrical properties of the 35Na2O-25V2O5-(40 - x)P2O5 - xNb2O5 system is examined. The starting glass shows the highest values of DC conductivity, σDC, reaching 1.45 × 10-8 Ω-1 cm-1 at 303 K, along with a glass transition temperature, Tg, of 371 °C. The incorporation of Nb2O5 influences both σDC and Tg, resulting in non-linear trends, with the lowest values observed for the glass with x = 20 mol%. Electron paramagnetic resonance measurements and vibrational spectroscopy results suggest that the observed non-monotonic trend in σDC arises from a diminishing contribution of polaronic conductivity due to the decrease in the relative number of V4+ ions and the introduction of Nb2O5, which disrupts the predominantly mixed vanadate-phosphate network within the starting glasses, consequently impeding polaronic transport. The mechanism of electrical transport is investigated using the model-free Summerfield scaling procedure, revealing the presence of mixed ionic-polaronic conductivity in glasses where x < 10 mol%, whereas for x ≥ 10 mol%, the ionic conductivity mechanism becomes prominent. To assess the impact of the V2O5 content on the electrical transport mechanism, a comparative analysis of two analogue series with varying V2O5 content (10 and 25 mol%) is conducted to evaluate the extent of its polaronic contribution.

Reversible Enhancement of Electronic Conduction Caused by Phase Transformation and Interfacial Segregation in an Entropy‐Stabilized Oxide

AbstractEntropy‐stabilized oxide (ESO) research has primarily focused on discovering unprecedented structures, chemistries, and properties in the single‐phase state. However, few studies discuss the impacts of entropy stabilization and secondary phases on functionality and in particular, electrical conductivity. To address this gap, electrical transport mechanisms in the canonical ESO rocksalt (Co,Cu,Mg,Ni,Zn)O are assessed as a function of secondary phase content. When single‐phase, the oxide conducts electrons via Cu+/Cu2+ small polarons. After 2 h of heat treatment, Cu‐rich tenorite secondary phases form at some grain boundaries (GBs), enhancing grain interior electronic conductivity by tuning defect chemistry toward higher Cu+ carrier concentrations. 24 h of heat treatment yields Cu‐rich tenorite at all GBs, followed by the formation of anisotropic Cu‐rich tenorite and equiaxed Co‐rich spinel secondary phases in grains, further enhancing grain interior electronic conductivity but slowing electronic transport across the tenorite‐rich GBs. Across all samples, the total electrical conductivity increases (and decreases reversibly) by four orders of magnitude with heat‐treatment‐induced phase transformation by tuning the grains’ defect chemistry toward higher carrier concentration and lower migration activation energy. This work demonstrates the potential to selectively grow secondary phases in ESO grains and at GBs, thereby tuning the electrical properties using microstructure design, nanoscale engineering, and heat treatment, paving the way to develop many novel materials.

Coordination environment-induced ionic–electronic transport transition in LiVO3

Lithium metavanadate (LiVO3) is a typical ionic conductor with a monoclinic pyroxene-type structure at ambient conditions. Here, we investigated the structural and electrical transport properties of LiVO3 under high pressures by combining in situ Raman scattering, x-ray diffraction, impedance spectroscopy measurements, and first-principles calculations. All experimental and theoretical results demonstrated that LiVO3 undergoes a structural transition from monoclinic to triclinic phase at around 5 GPa, during which partial VO4 tetrahedrons are transformed into a VO6 octahedron. The ion migration of LiVO3 was significantly suppressed above 5 GPa and an ionic–electronic transition was discovered at 10.7 GPa. The structural evolution involving coordination environment change results in an electron density rearrangement around Li and O atoms, which are responsible for the transformation of electrical transport mechanism in LiVO3 under high pressures. These results expand our understanding of the electrical and structural properties of LiVO3 under high pressures and provide insights into the pressure effects on ion migration in solid electrolytes.

Optical, morphological and electrical properties of rapid thermally annealed CoPc/n-Ge heterostructures for photodiode applications

Effect of rapid thermal annealing (RTA) temperature on electrical, morphological and optical properties of cobalt phthalocyanine (CoPc)/n-Ge heterostructures is investigated. UV–Vis measurements of as-deposited and annealed CoPc thin films show the presence of Q band transition at 618 nm and 690 nm absorption wavelength suggesting π-π* transitions. A phase transition is evidenced for the 300 °C annealed CoPc sample. Further, no degradation of Q band intensities is noticed which signifies highly stable CoPc thin films even after annealing at 400 °C. AFM measurements of CoPc thin film on Ge substrate reveal an increased RMS roughness with increased annealing temperature until 200 °C and further roughness was found to be decreased for the sample annealed at 300 °C. A clear change in the morphology of CoPc thin films is observed for the 300 °C annealed sample than 200 °C annealed sample which shows an evidence for the phase transition of CoPc thin films from α-phase to β-phase. This phase transition of CoPc thin films was also confirmed using XRD measurements. FESEM with EDS measurements were carried out for the as-deposited and annealed heterostructures. The surface topography of all the samples reveals a spherical-grained morphology and the grains seem to be highly dispersed in 400 °C annealed CoPc/Ge layers. The electrical and current transport mechanisms of the Au/CoPc/n-Ge heterostructure have been explored at different annealing temperatures by using I–V and C–V characteristics. Notably, the results reveal that superior barrier parameters are observed for the heterostructure annealed at 300 °C than as-deposited heterostructure. Rapid thermal annealing of the Au/CoPc/Ge heterostructure shows its promising applications in the areas of optoelectronic or photoresponsive devices.

Mixed Ionic Electronic Conduction Caused by Phase Transformation and Interfacial Segregation in an Entropy Stabilized Oxide

Research on entropy-stabilized oxides (ESO) [1] has primarily focused on exploring new single-phase structures with diverse chemistries, or unique properties, such as high Li-ion conductivity, high dielectric constant, low thermal conductivity, good electrochemical cycling stability, and high storage capacity retention [2]. However, few studies discuss the impact of secondary phase formation on functionality such as electrical conductivity [3] despite the fact that annealing this single-phase ESO causes it to undergo a phase transformation leading to the formation of Cu-rich and Co-rich secondary phases [4]. To address this gap, this work [5] investigates the electrical transport mechanisms in the canonical entropy-stabilized oxide (Co,Cu,Mg,Ni,Zn)O as a function of secondary phase content. Here, the structure and composition of single-phase and multiphase ESOs, and their GBs and HIs are probed using atomic-resolution imaging by scanning transmission electron microscopy (STEM) coupled with nanoscale spectroscopy by electron energy-dispersive spectroscopy (EDS) and electron energy-loss spectroscopy (EELS). Our findings suggest that when single-phase, the oxide is an oxygen ion conductor. After 2 h of heat treatment, Cu-rich tenorite particles form at some grain boundaries, turning the grain interior rocksalt oxide into a mixed ionic-electronic conductor via oxygen ions and small hole polaron Co2+/Co3+ and Cu2+/Cu+ pairs. 24 h of heat treatment leads to the full coverage of Cu-rich tenorite particles at all grain boundaries and the formation of anisotropic Cu-rich tenorite and equiaxed Co-rich spinel particles in the grains. While the grain interiors exhibit similar mixed ionic-electronic conduction, Cu-rich tenorite grain boundary phases create a pathway for Cu2+/Cu3+ small hole polarons. The ability to selectively grow secondary phases nucleated at grain boundaries enables tuning of electrical properties in entropy-stabilized and complex concentrated oxides using microstructure design, nanoscale engineering, and heat treatment, paving the way to develop many novel materials.[1] C. M. Rost, J.-P. Maria, Nat Commun, 2015.[2] A. Salian, S. Mandal, Critical Reviews in Solid State and Materials Sciences, 2022.[3] M. Moździerz, K. Świerczek, Acta Materialia, 2021.[4] A. D. Dupuy, J. M. Schoenung, Journal of the European Ceramic Society, 2021.[5] H. Vahidi...W. J. Bowman (submitted). Acknowledgments This research was primarily supported by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967). WJB and HV acknowledge partial support from the UCI new faculty startup funding. The authors acknowledge the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI) supported in part by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967).

Electrical transport mechanism of manganite-based trilayer heterostructures in the Cusp and insulating regions

In the present study, efforts are made to study the temperature dependent resistivity (ρ-T) variations of manganites (La0.7Sr0.3MnO3 (LSMO) single layer) and manganites-based systems ((LSMO/γ-Fe2O3/LSMO) trilayer heterostructures) in two distinct regions (Cusp region and Insulating region). Cusp region is an intermediate region between Metallic region and Insulating region. The resistivity-temperature curves are studied and analysed by various resistive models and fitting equations. The co-existence of ferromagnetic clusters and polarons manifests in the Cusp region. The Insulating region is explored and fitted under two regimes: Low Temperature Insulating region and High Temperature Insulating region. Various mathematical models viz. Thermal Activation model, Small Polaron Hopping model and Variable Range Hopping model were employed to study the ρ-T variations under various temperature ranges for LSMO (60 nm) single layer system and LSMO/γ-Fe2O3/LSMO (150 nm) trilayer heterostructures. In Insulating region, the deviations in the fitted curves from the experimental data is due to intrinsic disorder at the R/A site in case of LSMO single layer system while in case of trilayer system disorder exists at both R/A and B sites. The study is crucial to understand the microscopic picture of electrical transport behavior in both the systems near and above Metal-Insulator Transition.

Studies on thermoelectric performance of pristine and Selenium alloyed Bismuth Sulfide crystals grown by vertical Bridgman technique

By using Vertical Bridgman Technique (VBT), pure and Selenium alloyed Bismuth Sulfide crystals were grown. Effect of Selenium concentration on structural, electrical and thermal transport properties with respect to pristine crystal is thoroughly studied. Grown crystals were characterized by Energy Dispersive analysis of X-rays (EDAX), Field Emission Scanning Electron Microscopy (FE-SEM) and Powder X-ray Diffraction (PXRD) to confirm stoichiometry, surface morphology and structure respectively. Hall effect measurement is done to determine carrier concentration and mobility. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured from 303K to 773K to study electrical and thermal transport mechanism. Electrical conductivity was increased from 3.84 S/cm to 33.34 S/cm with increasing Se concentration while Seebeck coefficient showed an opposite trend. Power factor also showed enhancement from 1.43 μW/cmK2 to 2.70 μW/cmK2 with Se substitution. Pristine S1 (Bi1.97S3.19) showed figure of merit ZT = 0.23 at 683K while maximum ZT = 0.54 at 733K was obtained for S4 (Bi1.97S2.88Se0.3) crystal. This study indicated that appropriate concentration of Selenium is beneficial to improve thermoelectric performance of Bismuth Sulfide.

Fe dopant controlled the ferromagnetic, structural, thermal, optical, and electrical characteristics of CdO nanoparticles

This research paper presents a study on (Fe) doped CdO nanoparticles focusing on their structural (XRD), thermal (TGA and DTA), optical (UV–vis), magnetic (VSM and ESR), and electrical characteristics. The synthesis of Cd1-xFexO with (x = 0.0, 0.01, 0.05, 0.10, 0.15, and 0.20) nanoparticles was carried out using the co– precipitation technique. Fe dopants showed a great impact on the structural parameters and the thermal stabilities of obtained nanomaterials. SEM and TEM imaging techniques are employed to investigate the morphology, size, and distribution of the Cd1-xFexO nanoparticles. UV spectroscopy was employed to better understand the electronic transitions and optical characteristics. Furthermore, magnetization measurements from ESR and VSM showed a weak ferromagnetic order with a high Fe concentration. For instance, the Ac electrical conductivity measurements were used to determine the electrical properties, dielectric losses, and charge transport mechanisms between the Fe-dopants and CdO. The structural, thermal, optical, magnetic, and electrical characteristics data are complemented to better understand for Cd1-xFexO materials for employing them in magnetic storage and sensors, photocatalysis, other future applications.

Dielectric relaxation and conductivity phenomena in ferroelectric ceramics at high temperatures

The issues related to microstructure and its effects on functional properties of electroceramics become increasingly prominent with the progressive downscaling of electronics. In this study, temperature-dependent dielectric and impedance data of BaTiO3 (BT), Sr-doped BT (BST) and layer-structured BaBi4Ti4O15 (BBTO) ceramics are systematically investigated to reveal the effects of doping and perovskite layering on the dielectric relaxation and conduction processes at high temperatures. By using complex impedance spectroscopy, it is demonstrated that the ceramics are electrically heterogeneous structures displaying a non-ideal Debye-like behavior at high temperatures. Using a suitable equivalent circuit model, the impedance diagrams at different temperatures are simulated and the refined values of macroscopic resistance and capacitance are used for the identification and characterization of particular microstructural regions (grains, grain boundaries, interfaces, etc.). The approach of combining the impedance, electric modulus and permittivity formalisms is demonstrated to be effective in explaining the peculiarities of the electrical charge transport mechanism and relaxation in the grains, grain boundaries and interface layers of the ceramics.

Grain boundary passivation in cuprous oxide thin films via nitrogen annealing

In this work, polycrystalline cuprous oxide (Cu2O) films deposited by magnetron sputtering were annealed in situ in N2 atmospheres. Room-temperature and temperature-dependent Hall-effect measurements were performed on as-deposited and N2-annealed Cu2O films to probe the electrical transport mechanisms. The results show that the hole mobility of 0.8 Pa N2-annealed Cu2O film is enhanced compared with its as-deposited counterpart. It is shown that at low temperatures, the hole mobilities of Cu2O films appear to be limited by grain boundary scattering, while acoustic-phonon scattering comes into play at elevated temperatures. Moreover, the grain boundary potential barrier height which inhibits the hole transport is found to be reduced by N2-annealing at 0.8 Pa, thereby leading to the observed improvement in the hole mobility. It is thought that N2 is mainly concentrated at the grain boundaries in polycrystalline Cu2O films, thus passivating the grain boundary defect trap states. The results reported in this work suggest that N2-annealing induced grain boundary passivation could be an effective method to improve the photoelectric properties of polycrystalline Cu2O films.

Tunable electrical and impedance characteristics of Co–Zn doped M-type Sr Hexaferrites: Role of grain, grain boundaries, electrical transport mechanisms and software/circuit modeling

M-type hexaferrites SrCoxZnxFe12-2xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been synthesized using the sol-gel method. The structural, dielectric, and electrical properties of Zn2+ and Co2+ substituted strontium ferrite have been carried out. The dielectric and electric properties of prepared hexaferrites have been examined over the frequency range of 100 Hz to 2 MHz. The formation of the hexagonal phase has been confirmed by the X-ray diffraction (XRD) analysis. The substitution of Co2+ and Zn2+ causes a reduction in crystallite size from 39.50 to 26.42 nm being the smallest in the case of x = 1.0. Scanning electron microscopy (SEM) indicates the formation of honeycomb-like grain structures in composition x = 1.0. The dielectric spectrum shows that the dielectric constant and loss tangent vary non-monotonically with the doping of Co–Zn content. A non-Debye type relaxation is shown by the electric modulus of the prepared compositions. There is a reduction in relaxation time with the increase in doping of Co–Zn. The impedance spectra indicate the effects of both grain and grain boundaries on the electrical properties. The impedance analysis has been presented with the modeling of electrical processes in the samples using an equivalent circuit model comprising of parallel RC circuit for grains and grain boundaries. The obtained simulated results are in agreement with the measured results.

Comparative structure, optical and electrical characteristics of sol-gel-deposited In-, Ga-, and Sn-doped CuO thin films

Doping of metal-oxide thin films provides an effective method to improve the performance of various devices based on them such as solar cells, photodetectors, and gas sensors. Developing high-performance of these devices, the influence of In, Ga, and Sn dopants on structure, optical and electrical characteristics of CuO deserves further study. Herein, undoped and In-, Ga-, and Sn-doped CuO thin films are deposited on glass substrates by the sol-gel method, and the parameters influenced by these dopants are determined systematically. The effect of studied dopants on XRD, SEM, UV-vis, PL, and electrical conductivity measurements are examined, and the results are correlated with each other. Additionally, the electrical transport mechanism of the films is comprehensively investigated. It is determined that the multi-phonon hopping (MPH) conduction mechanism governs the temperature-dependent conductivity of the films. Finally, it is found that the probed dopants significantly impact the properties of CuO thin film.

Crystallographic dependence of the electrical transport mechanism in La-Mn-O thermosensitive thin films

Bimetallic oxide materials with amorphous state usually exhibit singular peculiarities due to their periodic disorder structure, implying great potential applications as high-performance electronic devices. In this report, La-Mn-O thin films with different crystallographic features (amorphous and polycrystalline) were deposited on Si (100) substrates using magnetron sputtering method. The as-deposited thin films were successfully convert from the amorphous state to the polycrystalline state by tuning the post-annealing temperatures. X-ray diffraction (XRD) confirmed that La-Mn-O was amorphous at annealing temperatures of 500 °C, while the films were polycrystalline at higher annealing temperatures (600 °C and 700 °C). Scanning electron microscopy (SEM) and high-magnification transmission electron microscopy (HRTEM) distinguished the microscopic features of LaMnO3 thin films in polycrystalline and amorphous states. The effects of annealing temperatures and structural disorder on the temperature-dependent electrical transport properties of La-Mn-O thin films are investigated. The resistance-temperature relationship curves of both polycrystalline and amorphous films show negative temperature coefficient behavior, and the amorphous films follow more than one conduction mechanism. Results show that the electrical transport of the crystalline La-Mn-O films is mainly controlled by thermal activation mechanism, while the electron transport behavior of the amorphous film is simultaneously influenced by thermal activation and Mott VRH variable range hopping conduction.

Low temperature magnetic and structural properties of Sr-doped La2CoMnO6 (La2-xSrxCoMnO6: 0 ≤ x ≤ 0.08) double perovskite nanoparticles

A study on crystal structure and physical properties has been performed on nanoparticles of lead-free double perovskites, La2CoMnO6 (LCMO) and Sr-doped La2-xSrxCoMnO6 (LSMO:0 ≤ x ≤ 0.08) prepared by the sol–gel synthesis method. In preparation for the LSMO nanoparticle, the La site of the LCMO double perovskite was replaced with an increasing concentration of Sr atom. Structural investigation done by employing the X-ray Diffraction technique indicates that the crystallite size decreases as the doping concentration increases. The Rietveld refinement on the XRD pattern shows the formation of the rhombohedral phase of LCMO (S.G. no. 161). Strain in the prepared samples estimated from Williamson Hall (W-H) analysis shows that the strain decreases as crystallite size decreases. The presence of compressive strain is also evident from the blue shift obtained in the Raman spectrum of the nanoparticles. The UV–Vis spectra reveal the maximum absorption in the near UV region of the electromagnetic spectrum. The Bandgap analysis from Tauc’s plot shows an increase in band gap with Sr doping in the LCMO host lattice (from 1.81 eV to 1.92 eV). This is attributed to the decrease in crystallite size and octahedral tilting with Sr doping. Resistivity versus temperature plots reveal the semiconducting nature of the compound. A linear nature graph between lnρ and T-14 indicates that the electric transport mechanism is governed by the variable range Hopping (VRH) model. The M−H curves show that the maximum magnetization decreases as a result of Sr doping due to the anti-site disorder introduced. dM/dT vs T curve shows two magnetic transitions at ∼ 215 K and at ∼ 173 K which are due to Co2+–O2--Mn4+ and Co3+–O2--Mn4+ ferromagnetic superexchange interactions, respectively.

The evaluation of the Al/ZnO/Si/Al heterojunction diode current-conducting mechanisms

This work focuses on the electrical transport and conduction mechanisms — inside a sprayed — made zinc oxide-on-p-type silicon junction device. A fabricated Al/ZnO/Si/Al heterojunction is characterized at 300 and 380[Formula: see text]K in the dark. The aforementioned theories predict that the current density (J) is an exponential function of measured voltage (V) and work temperature (T). Exponential equations are linearized as a result of a current conduction mechanism (CCM) kind. Useful parameters like barrier height [Formula: see text] of trap are extracted from the slope B. Ohmic and space charge limited current (SCLC) regimes inside are studied at 300 and 380[Formula: see text]K recording a shift in exponent as a result of temperature. Fowler–Nordheim (FN) conduction mechanism inside Al/ZnO/Si/Al device is considered slope and [Formula: see text] values are determined for two cited work temperatures. Our device presents a thermionic emission (TE) and exhibits an effect of temperature on slope and intercept values of (ln[Formula: see text]/A*[Formula: see text]) function. The Poole–Frenkel (PF) emission in terms of 1/V data are presented for 300 and 380[Formula: see text]K. Besides, PF emission mechanism in terms of 1/[Formula: see text] is exhibited and parameters are influenced by temperature. Behavior of conductance as a result of temperature is detailed and evidenced.

Lattice Dynamics of Quinacridone Polymorphs: A Combined Raman and Computational Approach.

Polarized low-frequency Raman microscopy and a posteriori dispersion-corrected density functional simulations are combined to investigate the lattice vibrations of the αI, β, and γ polymorphs of the model organic semiconductor quinacridone, which are known to display different optical and electronic properties. The comparison between experiments and calculations allows for unambiguous mode assignment and identification of the scattering crystal faces. Conversely, the agreement between simulations and experiments validates the adopted computational methods, which correctly describe the intermolecular interaction of the molecular material. The acquired knowledge of quinacridone lattice dynamics is used to describe the αI to β thermal transition and, most consequentially, to reliably characterize the electron-lattice phonon coupling strength of the three polymorphs, obtaining hints about the electrical transport mechanism of the material.

Influence of single and double interlayers on the electrical and current transport mechanism of Mo/n-Si Schottky diode and its microstructural and chemical properties

Influence of single and double interlayers on the electrical and current transport mechanism of Mo/n-Si Schottky diode and its microstructural and chemical properties