Increase In Charge Carrier Concentration Research Articles

Synthesis of Silicon and Higher Manganese Silicide Bulk Nano-composites and Their Thermoelectric Properties

In this work, silicon and higher manganese silicide (HMS) bulk nanocomposites were synthesized, Si100-x(HMS)x, where x is 10–50, and their thermoelectric properties were studied. The powders of Si and Mn in a stoichiometric ratio were mixed by a ball milling, followed by hot-pressing to obtain the Si + HMS bulk nanocomposite samples. Every bulk sample was highly dense, with a density of over 90% of its theoretical value. The x-ray diffraction analysis revealed that only the Si and HMS phases, without any impurity phase, were obtained. The fractured surface morphology showed that the composites consisted of micro-sized Si matrix grains with the HMS nanodots homogenously distributed within the grains. The thermoelectric studies showed that thermal conductivity decreased with a higher concentration of HMS, mainly due to the reduction of lattice thermal conductivity. It was believed to be the presence of the HMS nanodots which effectively scattered phonon transport. Furthermore, the addition of HMS increased charge carrier concentration. Hence, the Seebeck coefficient decreased, and the electrical conductivity increased with increasing HMS content. However, the presence of the HMS nanodots also contributed to strong scattering of charge carriers. The charge mobility was reduced significantly for the composite samples compared to the bulk Si sample. Therefore, the electrical conductivity is relatively low compared to the reported values in the literature. The dimensionless figure-of-merit (ZT) was improved in the nanocomposite samples compared to the bulk Si sample, and the values were largest for the sample with x = 50.

Ferroelectric order versus metallicity in Sr1−xCaxTiO3−δ ( x=0.009 )

We report on a thermal-expansion study of the ferroelectric phase transition in insulating Sr$_{1-x}$Ca$_x$TiO$_3$ ($x=0.009$) and its evolution upon increasing charge-carrier concentration up to $n\simeq 60 \times 10^{19}$cm$^{-3}$. Although electric polarization is screened by mobile charge carriers, we find clear signatures of the ferroelectric phase transition in the thermal-expansion coefficient $\alpha$ of the weakly doped metallic samples. Upon increasing $n$, the transition temperature $T_\mathrm{C}(n)$ and the magnitude of the anomalies in $\alpha$ rapidly decrease up to a threshold carrier density $n^\star$ above which broadened anomalies remain present. There is no indication for a sign change of $\alpha$ as is expected for a pressure-dependent quantum phase transition with $n$ as the control parameter. Thus, the ferroelectriclike transition is either continuously fading away or it transforms to another low-temperature phase above $n^\star$, but this change hardly affects the temperature-dependent $\alpha(T)$ data.

Improved TCO characteristics of ZnO:Si films via utilization of Si4+ ionized donor states and its application in n-SZO/p-Si heterojunction solar cells

Utilizing Si4+ ionized states providing two free electrons per atom, ZnO:Si (SZO) thin films have been grown as a superior transparent conducting oxide (TCO) material ideal for Si-based electronic devices. Energetically favoured substitutional doping of Zn2+ by Si3+ and Si4+ states facilitates increase in concentration (ne) and mobility (μ) of the charge carriers. At increased dopant incorporation at the interstitial sites Si2+ and Si1+ states are proportionally contributed which are not electronically active and act as scattering centres for the existing free electrons. Further, the formation of non-conducting SiOx bonds and their segregation at grain boundaries restrict increase in charge carrier concentration and reduce their mobility. The ideal dopant incorporation in ZnO:Si network accommodates ~1.6 ± 0.07 at.% Si. A minimal resistivity, (ρ)min ~7.16 × 10−5 Ωcm corresponding to the highest mobility, (μ)max ~85 V−1cm2s−1 and superior carrier density, (ne)max ~1.0 × 1021 cm−3 signify a highly degenerate semiconductor characteristic of the SZO films with reduced effective mass of electron, m* ~0.15 m0. Significantly high magnitude of Figure-of-Merit (FoM: Φ) ~9.7 × 10−2 Ω−1, even at moderately low growth temperature ~150 °C demonstrates excellent TCO characteristics of SZO films. The n-SZO/p-Si solar cells reveal increased VOC ~312 mV and JSC ~27.9 mA/cm2 via moderate widening in optical band gap and a significant increase in carrier concentration in the SZO component, respectively. The n-SZO/p-Si heterojunction solar cells with a FF ~0.499 and photovoltaic conversion efficiency η ~4.34% has been obtained with improved SZO layer grown by optimized doping via consumption of Si4+ donor states.

On the electric conduction of ZrO2 in the steady stage of flash sintering

The electric conductivity of zirconia in the steady stage of flash sintering is measured under various current densities. We find that the steady stage conductivity (σs) is higher than the normal conductivity (σn) measured at non-flashing conditions, even Joule heat is considered. The higher conductivity is ascribed to the increase in charge carrier concentration. The difference between σs and σn is then used to estimate the oxygen vacancy concentration. It is found that the concentration increases with increasing current density at beginning and then decreases with further increasing current density. A speculative explanation is proposed to account for this phenomenon.

Efficient UV photodetectors based on Ni-doped ZnS nanoparticles prepared by facial chemical reduction method

Ni-doped ZnS nanoparticles are synthesized by simple hydrothermal process for the utilization in UV photodetectors. Surface morphology of the prepared samples is investigated through high resolution transmission electron microscopy (HRTEM), which reveals that the prepared nanoparticles are smaller than 20 nm. The well visualized selected area electron diffraction rings suggests the nanocrystalline nature of the prepared nanoparticles with (hkl) planes (111), (220) and (311). The structural analysis is done by x-ray diffraction (XRD) studies; which reveal the decrease in crystallite size with increase in Ni-doping concentration. The device performance of the photodetectors is tested under UV-A light (wavelength ≈365 nm) and found that the ability of the prepared devices increases with increase in Ni-doping concentration. This can be attributed to the enhanced surface to volume ratio and increase in charge carrier concentration. The adsorption-desorption of oxygen molecules on the nanoparticles' surface is considered to be the mechanism for UV photodetection.

Charge Transport in Nonstoichiometric 2-Fluoropyridinium Triflate Protic Ionic Liquids

Pyridinium triflate protic ionic liquids have been demonstrated to be highly dissociated, and nonstoichiometric compositions have been used in protic energy devices such as the all-organic proton battery. Herein, we use a combination of pulsed field gradient NMR spectroscopy and electrochemical impedance spectroscopy to investigate the charge transport properties of the nonstoichiometric protic ionic liquid 2-fluoropyridinium triflate and the variation with acid doping level. While all diffusion coefficients decreased with the amount of acid doping, the room temperature conductivity increased due to the concurrent increase in charge carrier concentration. The maximum room temperature conductivity was 7.33 mS/cm, obtained when 14% of the pyridine was protonated with triflic acid, while higher acid doping levels lead to liquid/solid mixtures with low conductivity. PEDOT supercapacitor cells with this electrolyte demonstrated very high capacitance (83.9 F/g) and charge storage capacity (23.3 mAh/g). In addition we predict that using a lower acid doping level than previously will result in superior electrolyte performance in proton batteries due to improvements in conductivity, processability and electrochemical stability. (Less)

Ni/Fe Codoped In2S3 Nanosheet Arrays Boost Photo‐Electrochemical Performance of Planar Si Photocathodes

AbstractThe photo‐electrochemical performance of the Si photocathode is seriously restricted by the severe charge recombination at the Si/electrolyte interface and sluggish hydrogen evolution reaction (HER) kinetics. Herein, a facile hydrothermal process is reported to integrate Ni/Fe codoped In2S3 nanosheet arrays onto the surface of unmodified a p‐Si photocathode for water reduction. The experimental results and density functional theory calculations indicate that the Ni and Fe codoping of In2S3 contributes to small surface transfer impedance, prolonged carrier lifetime, increased charge carrier concentration, and reduced overpotential for HER. Moreover, a p–n junction formed at the interface of Si and Ni/Fe:In2S3 promotes the photogenerated electron–hole separation and reduces the recombination in the bulk. As a result, the Si–Ni/Fe:In2S3 photocathode exhibits high performance with significantly enhanced photocurrent of −80.9 mA cm−2 at −1.3 VRHE and positive onset potential of 0.44 VRHE.

A Bi/BiOI/(BiO)2CO3 heterostructure for enhanced photocatalytic NO removal under visible light

Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi2O2CO3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO)2CO3, the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and BiOI/(BiO)2CO3), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO)2CO3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO)2CO3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.

Reactive spark plasma sintering and thermoelectric properties of Nd-substituted BiCuSeO oxyselenides

Bi1-xNdxCuSeO (x = 0; 0.05; 0.10; 0.15) was fabricated by the solid-state reaction and the reactive spark plasma sintering for comparative study. It was demonstrated that BiCuSeO could be formed in-situ by the reaction between Bi2O3, Bi, Cu and Se during the densification process. The effect of Nd doping on the thermoelectric properties has been investigated. The results indicated that for both series of the samples the substitution of Bi3+ by Nd3+ resulted in the increase of charge carrier concentration mainly caused by Bi/Cu deficiencies formation with the substitution. However, the specimens obtained by reactive spark plasma sintering had lower hole concentration which may originate from the high speed of the process resulted in induced point defect and interface scattering and another phase formation mechanism leading to the smaller amount of Bi/Cu deficiencies.

Control of Charge Recombination in Perovskites by Oxidation State of Halide Vacancy.

Advances in perovskite solar cells require development of means to control and eliminate the nonradiative charge recombination pathway. Using ab initio nonadiabatic molecular dynamics, we demonstrate that charge recombination in perovskites is extremely sensitive to the charge state of the halogen vacancy. A missing iodine anion in MAPbI3 has almost no effect on charge losses. However, when the vacancy is reduced, the recombination is accelerated by up to 2 orders of magnitude. The acceleration occurs due to formation of a deep hole trap in the singly reduced vacancy, and both deep and shallow hole traps for the doubly reduced vacancy. The shallow hole involves a significant rearrangement of the Pb-I lattice, leading to a new chemical species: a Pb-Pb dimer bound by the vacancy charge, and under-coordinated iodine bonds. Hole trapping by the singly reduced iodide vacancy operates parallel to recombination of free electron and hole, accelerating charge losses by a factor of 5. The doubly reduced vacancy acts by a sequential mechanism-free hole, to shallow trap, to deep trap, to free electron, and accelerates the recombination by a factor of 50. The study demonstrates that iodine anion vacancy can be beneficial to the performance, because it causes minor changes to the charge carrier lifetime, while increasing charge carrier concentration. However, the neutral iodine and iodine cation vacancies should be strongly avoided. The detailed insights into the charge carrier trapping and relaxation mechanisms provided by the simulation are essential for development of efficient photocatalytic, photovoltaic, optoelectronic and related devices.

Structural and electrical properties of titanium-doped yttrium niobate

In this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type dopant which charge is mainly compensated by oxygen vacancies, moreover, it may adopt different valence states, therefore, oxygen ion-, proton- and electronic-type conductivity are expected. Very interesting, non-monotonic changes in electrical and structural properties as a function of titanium content were observed. The competition between the increasing charge carrier concentration and structural phenomena such as short-range pyrochlore ordering and/or vacancy clustering was proposed as responsible for this non-monotonicity.

Superconductive (Cu)TTF@TCNQ Nanosheets Detected By Peakforce Tunneling Atomic Force Microscopy

Superconductive (Cu)TTF@TCNQ Nanosheets have been deposited in various thicknesses and characterized through peakforce tunneling AFM. TTF (Tetrathiofulvalene) and TCNQ (tetracyanochinodimethan) are conjugated organic molecules. However, they formed a “metallic conductive interface”, by a charge transfer (CT) complex. Whereby TCNQ is an acceptor molecule and TTF is a donor molecule. [1] Such charge transfer (CT) complexes possess an increased charge carrier concentration within the TTF@TCNQ nanosheets producing hole and electron carriers, donors and anions with holes, or cations and acceptors with electrons. Therefore, superconductivity have been reported for this system. [ 2,3 ] Cu:TTF and Cu:TCNQ nanosheets have been deposited by in different thicknesses by various methods, e.g. spin-coating, dip-coating or electrodeposition methods. The thicknesses have been performed in the range of 2 nm to 30 nm. Peakforce tunneling AFM measurements can be performed on this systems. This TUNA characterizes ultra-low currents (<1pA) through the thickness of nanosheets, and is of particular importance when electrical characterization of conductivity samples is needed at high lateral resolution. High-resolution current mappings of these nanosheets were enabled as well as the corresponding morphology images. Moreover, The I-V currents in the range from pA to nA of these nanosheets have been detected due to the high sensitivity and accuracy of the Peakforce TUNA mode. The resistances of the (Cu)TTF@TCNQ nanosheets can be calculated by using this currents and then the conductivities were also been obtained accordingly. These superconductive nanosheets will help to construct novel porous superconductive SURMOF hybrid materials in the near future for various device applications. R eference Tang, Q.; Zhou, Z.; Chen, Z. J. Phys. Chem. C, 2011, 115, 18531–18537.Kirtley J. R.; Mannhart, J. Nat. Mater., 2008, 7, 520-521.Alves, H.; Molinari, A. S.; Xie, H.; Morpurgo, A. F. Nat. Mater., 2008, 7, 574-580 Figure 1

Bismuth vacancy mediated single unit cell Bi2WO6 nanosheets for boosting photocatalytic oxygen evolution

Surface defects are critically important for photocatalytic reactions. Compared with the widely studied oxygen vacancies, engineering metal vacancies into photocatalysts and study the effect of metal vacancies on the photocatalytic performance is seldom reported. Herein, we engineering bismuth vacancies into Bi2WO6 via a template-directed strategy to form single unit cell ultrathin nanosheets. Aberration-corrected scanning transmission electron microscopy reveals the formation of bismuth vacancies in the Bi2WO6 ultrathin nanosheets. Density functional theory calculations suggest that the presence of bismuth vacancies create a new defect level in forbidden band and increased density of states at the valence band maximum, resulting in increased charge carrier concentration and electronic conductivity. Moreover, the bismuth vacancy structure benefit for the surface adsorption and activation of water molecule, which favors the water oxidation reactions. As a result, the prepared bismuth vacancy-rich Bi2WO6 exhibit significantly increased visible light photocatalytic oxygen evolution activity than the corresponding bulk Bi2WO6, which is the more challenging half-reaction for fuel-forming due to the sluggish reaction kinetics. This work open the door for designing other metal vacancies engineered photocatalysts via ultrathin-control strategy and achieving highly efficient photocatalytic performances.

Electrical and Optical Tunability in All-Inorganic Halide Perovskite Alloy Nanowires.

Alloying different semiconductors is a powerful approach to tuning the optical and electronic properties of semiconductor materials. In halide perovskites (ABX3), alloys with different anions have been widely studied, and great band gap tunability in the visible range has been achieved. However, perovskite alloys with different cations at the "B" site are less understood due to the synthetic challenges. Herein, we first have developed the synthesis of single-crystalline CsPb xSn1- xI3 nanowires (NWs). The electronic band gaps of CsPb xSn1- xI3 NWs can be tuned from 1.3 to 1.78 eV by varying the Pb/Sn ratio, which leads to the tunable photoluminescence (PL) in the near-infrared range. More importantly, we found that the electrical conductivity increases as more Sn2+ is alloyed with Pb2+, possibly due to the increase of charge carrier concentration when more Sn2+ is introduced. The wide tunability of the optical and electronic properties makes CsPb xSn1- xI3 alloy NWs promising candidates for future optoelectronic device applications.

Impact of different layers on performance of OLED

This paper explores how different layers in an organic light emitting diode (OLED) impacts its performance. Here, different layers of OLED similar to hole/electron injection layer, transport layer, and block layers are analyzed. Four experimental devices are taken into consideration and their results are compared to one over another to analyze the impact of every layer. Inside depth analysis is also performed on the device to inspect what really is happening Innermost of the OLED. It is noticed that hole and electron block layer are instrumental in improving the device luminescence performance and efficiency. There is an improvement of 16, 37 and 38% in the luminescence of the device when hole block layers and electron block layers are added. Internal device analysis reveals that increase in charge carrier concentration and carrier confinement are the reason for this improvement.

Activation of amorphous Bi2WO6 with synchronous Bi metal and Bi2O3 coupling: Photocatalysis mechanism and reaction pathway

Amorphous semiconductors usually suffer from low photocatalysis efficiency due to the fast charge recombination rate. In this work, to activate the amorphous Bi2WO6, Bi2O3 and Bi particles were in sequence deposited over its surface via a facile in situ chemical reduction of amorphous Bi2WO6 by NaBH4 at room temperature. In the resultant ternary Bi/Bi2O3/Bi2WO6, the well-formed heterojunctions (i.e. Bi-Bi2O3 and Bi2O3-Bi2WO6) and the surface plasmon resonance effect of Bi both contribute to an increase in charge carrier concentration, an efficient e−/h+ separation and then an enhanced visible light photocatalytic performance. The molar ratio of Bi, Bi2O3 and Bi2WO6 in composite can be modulated by the dosage of NaBH4, and consequently the amount of each heterojunction (i.e. Bi/Bi2O3 or Bi2O3/Bi2WO6) as well as the intensity of SPR effect could be tuned. The photocatalytic NO removal test under visible light irradiation shows that BWO-0.8 (0.8 denotes the molar ratio of NaBH4 to Bi2WO6) presents a maximum NO removal efficiency of 55.4%, much higher than that of the pristine amorphous Bi2WO6 (10%). The enhanced activity can be attributed to the balanced SPR effect of Bi metal and the heterojunction effect, making their overall contribution maximized. The pathway study of photocatalytic NO oxidation by in situ FT-IR suggests that NO is converted to nitrates adsorbed over the catalyst surface. The present work could provide a new approach to activate the amorphous semiconductors for efficient visible light photocatalysis.

Enhancing thermoelectric performance of the CH3NH3PbI3 polycrystalline thin films by using the excited state on photoexcitation

Abstract Recently, organic-inorganic hybrid perovskite materials (CH3NH3PbI3) have made great progress in the solar cells field, however its thermoelectric properties are not good, one of the reason is that the carrier concentration is too low, resulting in low electrical conductivity. Another reason is that the phase structure changes from the tetragonal phase to the cubic phase when the temperature over 57 °C, which distorted the octahedron structure of PbI6. The structural distortion restricted the carrier's transport, leading to decreasing of the carrier's mobility. And the Seebeck coefficient was also rapidly dropped with the temperature increasing. In this article, we used photoexcitation-generated excited states could effectively restrain the decrease of electrical conductivity and Seebeck coefficient of CH3NH3PbI3 polycrystalline thin film, because the photoexcitation could greatly enhance the density of excited state, which increased charge carrier concentration and electrical conductivity. Moreover, thanks to the photoexcitation, the surface charge accumulation was increased significantly, enhancing the surface polarization at metal/Perovskite interface, simultaneously, enhancing the polarization effect of CH3NH3PbI3. The enhanced surface polarization functions as an additional driving force to diffuse the charge carriers from hot side to cold side, thus the carrier mobility was increased effectively, restraining the Seebeck coefficient's decrease caused by the crystal phase transition. Our experimental results showed that photoexcitation increased the electrical conductivity from 7.8 × 10−6 S/m in the dark to 4 × 10−5 S/m in illumination condition, the mobility increased from the 0.141 cm2/v.s in the dark to 13.122 cm2/v.s in illumination condition. Simultaneously, the Seebeck coefficient was also increased from 26 μV/K to −17 mV/K with increasing light intensity from 0 to 100%. The Power Factor (PF) value of 11.51 nW/mK2 in the illumination condition was further bigger than the PF of 5.27 × 10−6 nW/mK2 in the dark condition. As a result, our experiment further demonstrated that photoexcitation can be used as an effective way to simultaneously develop high Seebeck coefficient and electrical conductivity through excited states in an organic-inorganic semiconducting material with multilayer electrode/perovskite/electrode thin-film device.

Improved Charge Injection of Metal Oxide Thin‐Film Transistors by Stacked Electrodes of Indium Tin Oxide Nanoparticles and Silver Nanowires

AbstractSolution processed transparent electrodes are developed combining indium tin oxide nanoparticles (ITO‐NPs) and silver nanowires (Ag NWs) at low process temperature of 100 °C, compatible with solution processed indium gallium zinc oxide (IGZO) thin‐film transistors as source and drain electrodes. Four structures with various stacking of ITO‐NPs and Ag NWs are investigated. Although sole ITO‐NPs cannot provide the conductivity electrical properties of devices, including the mobility, threshold voltage, and subthreshold swing, are improved using ITO‐NPs over/under the Ag NWs. The mobility is enhanced by employing a hybrid electrode structure from 0.004 cm2 V−1 s−1 (single layer) to 3.42 cm2 V−1 s−1 (triple layer). The ultraviolet photoelectron spectroscopy and UV–vis measurements reveal the electronic structure to confirm the increase of charge carrier concentration at the interface, when ITO‐NP/IGZO heterojunction is formed. The ITO‐NP layer acts as a buffer layer between the IGZO and Ag NWs layer to facilitate charge injection to reduce the contact resistance, while the Ag NWs supply conductivity. These are also confirmed by Hall measurement and contact resistance extraction. Hybrid electrodes developed here are promising approach for solution processed transparent electrodes toward transparent and flexible electronics with advantages of low‐cost process excluding vacuum system.

Physical properties of solution processable n-type Fe and Al co-doped ZnO nanostructured thin films: Role of Al doping levels and annealing

The role of annealing temperature and Fe and Al co-doping on structural, optical, electrical and magnetic properties of solution processable ZnO thin films were investigated. ZnO:Fe thin films fixed with 2% of typical ferrous component were obtained to examine the role of 1–10% Al doping. X-ray diffraction analyses clearly indicates that the films to be polycrystalline and preferentially oriented along the c-axis of the hexagonal wurtzite structure. The film thickness, homogeneous distribution and decreasing/increasing of grain size dependence on Al content/annealing temperature (TA) were assessed by scanning electron microscopy. X-ray photoelectron spectroscopy revealed that Al3+ and Fe2+ ions to substitute for Zn2+ without changing the wurtzite structure. A slight decrease in the optical band gap of ZnO at fixed Fe dopant and a considerable increase of the optical band gap with increased Al doping concentrations and TA were observed. The refractive index increases with the fixed Fe dopant level and then decreases by Al doping levels, whereas the extinction coefficient clearly increases depended on both of Fe and Al concentrations. The refractive index and extinction coefficient both decrease with TA. Hall measurements show n-type conductivity and the increase of charge carrier concentration by Al doping levels and TA. Magnetic studies indicate room temperature ferromagnetism in Al and Fe co-doped ZnO thin films, whereas no room temperature ferromagnetism for the Fe-doped ZnO thin films was observed. An enhanced room temperature ferromagnetism in Al and Fe co-doped ZnO thin films was observed to depend on TA.

Influence of Cu incorporation on ionic conductivity and dielectric relaxation mechanism in NiO thin films synthesized by CBD

We present the influence of copper incorporation on ionic conductivity and dielectric relaxation mechanism of NiOthin films deposited by chemical bath deposition (CBD) method in this report. Structural and optical characterization of NiO and Cu:NiO thin films were carried out using XRD and UV–Vis spectroscopy. Increase in grain size and decrease in average microstrain in doped films were confirmed from XRD analysis. The spectrophotometric measurement shows band gap decreases with increase in dopant concentration. Impedance spectroscopy, modulus spectroscopy and dielectric study has been performed for ac electrical characterization. Impedance spectroscopy analysis confirmed enhancement of ac conductivity withCu incorporation suggesting an increase in charge carrier concentration due to doping. Enhancement in both real and imaginary part of dielectric constant was observed with Cu doping in NiO thin films. Activation energy to electrical transport process was determined from dc conductivity analysis and migration energy of charge carriers was determined from modulus spectroscopy analysis. Cole–Cole plot shows both grain and grain boundary contributes towards total resistance and capacitance. The overall resistance was found to decrease with Cu incorporation in NiO thin film. The observed results suggest hopping mechanism of charge carriers towards electrical conduction process.