Table of contents

The author investigates an intra-layer coupling effect through transverse acoustic (TA) phonon modes along the z-direction at Au nanoparticle (NP)–graphene monolayer (GM)–Au thin film (TF) plasmonic junctions in regard with sp³ type defect effect. The oxidation and resulting disorder of GM with breaking of six-fold symmetry have been explored. Because a Raman-forbidden D peak can be activated due to unwanted single-phonon inter-valley and intra-valley scattering processes, the quantitative estimation of the sp³ type defect is being performed by the intensity ratio between G and D peaks. By exploring the difference of the maximum peak position (TA3-TA1) and the intensity ratio, (TA1/TA3) the author can reveal that a lower z-protruded GM accompanied with weak intra-coupling and a weaker RBLM intensity show relatively high D/G. It means that larger surface area of a GM to be functionalized by oxidization can secure more easily than the higher z-protruded. This investigation presents the importance of controlling the degree of z-protrusion of GM surface in terms of not only the presence of high D/G but also its related and detailed nano-structural surface shape, leading to the enhancement of electrical properties such as a carrier mobility and sheet resistance value. The out-of-plane phonon modes will be considered as a key factor in further exploring nano-physical deformation of 2D materials in sync with its electrical performance.

A radio frequency RF atmospheric pressure plasma jet was used to enhance the wettability of cellulose-based paper of 90 g m⁻² and 160 g m⁻² grammage as a perspective platform for antibiotic sensitivity tests. Helium and argon were the carrier gases for oxygen and nitrogen; pure water and rapeseed oil were used for goniometric tests. The influence of the flow rate and gas type, the power of the discharge, and distance from the nozzle was examined. The surface structure was observed using an optical microscope. Attenuated total reflection Fourier transform infrared (ATR–FTIR) spectra were investigated in order to determine whether cellulose degradation processes occurred. The RF plasma jet allowed us to decrease the surface contact angle without drastic changes in other features of the tested material.

Experiments confirmed the significant influence of the distance between the treated sample and reactor nozzle, especially for treatment times longer than 15 s due to the greater concentration of reactive species at the surface of the sample, which decreases with distance—and their accumulation effect with time. The increase of discharge power plays an important role in decreasing the surface contact angle for times longer than 10 s. Higher power had a positive effect on the amount of generated active particles and facilitated the ignition of discharge. However, a too high value can cause a rise in temperature of the material and heat-caused damage.

American Foulbrood is a severe, notifiable disease of the honey bee. It is caused by infection of bee larvae with spores of the gram-positive bacterium Paenibacillus larvae. Spores of this organism are found in high numbers in an infected hive and are highly resistant to physical and chemical inactivation methods. The procedures to rehabilitate affected apiaries often result in the destruction of beehive material. In this study we assess the suitability of a double inductively coupled low pressure plasma as a non-destructive, yet effective alternative inactivation method for bacterial spores of the model organism Bacillus subtilis on beehive material. Plasma treatment was able to effectively remove spores from wax, which, under protocols currently established in veterinary practice, normally is destroyed by ignition or autoclaved for sterilization. Spores were removed from wooden surfaces with efficacies significantly higher than methods currently used in veterinary practice, such as scorching by flame treatment. In addition, we were able to non-destructively remove spores from the highly delicate honeycomb wax structures, potentially making treatment of beehive material with double inductively coupled low pressure plasma part of a fast and reliable method to rehabilitate infected bee colonies with the potential to re-use honeycombs.

Cold atmospheric-pressure plasma show promising antimicrobial effects, however the detailed biochemical mechanism of the bacterial inactivation is still unknown. We investigated, for the first time, plasma-treated Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria with Raman and infrared microspectroscopy. A dielectric barrier discharge was used as a plasma source. We were able to detect several plasma-induced chemical modifications, which suggest a pronounced oxidative effect on the cell envelope, cellular proteins and nucleotides as well as a generation of organic nitrates in the treated bacteria. Vibrational microspectroscopy is used as a comprehensive and a powerful tool for the analysis of plasma interactions with whole organisms such as bacteria. Analysis of reaction kinetics of chemical modifications allow a time-dependent insight into the plasma-mediated impact. Investigating possible synergistic effects between the plasma-produced components, our observations strongly indicate that the detected plasma-mediated chemical alterations can be mainly explained by the particle effect of the generated reactive species. By changing the polarity of the applied voltage pulse, and hence the propagation mechanisms of streamers, no significant effect on the spectral results could be detected. This method allows the analysis of the individual impact of each plasma constituent for particular chemical modifications. Our approach shows great potential to contribute to a better understanding of plasma-cell interactions.

An experimental study of the in-plane azimuthal behaviour and frequency dependence of the ferromagnetic resonance field and the resonance linewidth as a function of BiFeO₃ thickness is carried out in a polycrystalline exchange-biased BiFeO₃/Ni₈₁Fe₁₉ system. The magnetization decrease of the Pt/BiFeO₃/Ni₈₁Fe₁₉/Pt heterostructure with BiFeO₃ thickness deduced from static measurements has been confirmed by dynamic investigations. Ferromagnetic resonance measurements have shown lower gyromagnetic ratio in a perpendicular geometry compared with that of parallel geometry. The monotonous decrease of gyromagnetic ratio in perpendicular geometry as a function of the BiFeO₃ film thickness seems to be related to the spin–orbit interactions due to the neighbouring Pt film at its interface with Ni₈₁Fe₁₉ film. The enhancement of gyromagnetic ratio in Pt/Ni₈₁Fe₁₉/Pt is attributed to the Pt.

The in-plane azimuthal shape of the total linewidth of the uniform mode shows isotropic behaviour that increases with BiFeO₃ thickness. The study of the frequency dependence of the resonance linewidth in a broad band of 3–35 GHz has allowed the determination of intrinsic and extrinsic contributions to the relaxation as a function of BiFeO₃ thickness in perpendicular geometry. In our system the magnetic relaxation is dominated by the spin-pumping mechanism due to the presence of Pt. The insertion of BiFeO₃ between Pt and Ni₈₁Fe₁₉ attenuates the spin-pumping damping at one interface.

Recently, highly sensitive magnetic field sensors using the magnetoelectric effect in composite ferromagnetic-piezoelectric layered structures have been demonstrated. However, most of the proposed concepts are not useful for measuring dc magnetic fields, because the conductivity of piezoelectric layers results in a strong decline of the sensor's sensitivity at low frequencies. In this paper, a novel functional principle of magnetoelectric sensors for dc magnetic field measurements is described. The sensor employs the nonlinear effect of voltage harmonic generation in a composite magnetoelectric structure under the simultaneous influence of a strong imposed ac magnetic field and a weak dc magnetic field to be measured. This physical effect arises due to the nonlinear dependence of the magnetostriction in the ferromagnetic layer on the magnetic field. A sensor prototype comprising of a piezoelectric fibre transducer sandwiched between two layers of the amorphous ferromagnetic Metglas^® alloy was fabricated. The specifications regarding the magnetic field range, frequency characteristics, and noise level were studied experimentally. The prototype showed the responsivity of 2.5 V mT⁻¹ and permitted the measurement of dc magnetic fields in the range of ~10 nT to about 0.4 mT. Although sensor operation is based on the nonlinear effect, the sensor response can be made linear with respect to the measured magnetic field in a broad dynamic range extending over 5 orders of magnitude. The underlying physics is explained through a simplified theory for the proposed sensor. The functionality, differences and advantages of the magnetoelectric sensor compare well with fluxgate magnetometers. The ways to enhance the sensor performance are considered.

In this contribution we introduce a method of deep level spectroscopy in semi-insulating semiconductors demonstrated on detector-grade bulk CdZnTe. The method is based on the measurements of temporal and temperature evolution of the electric field profile in studied samples, which is very sensitive to a change of occupancy of deep levels. The measurement of the electric field is based on the linear electro-optic (Pockels) effect using the InGaAs avalanche photodiode with fast response. The internal electric field profile in studied samples significantly changes under various external conditions represented by the application of the bias and pulsed illumination with below-bandgap light. From the knowledge of the electric field behavior and using a standard analysis based on thermally induced transitions of electrons and holes from the deep levels to the conduction and valence bands, respectively, it is possible to get activation energies of the energy levels, their types (donor or acceptor) and corresponding capture cross-sections. By this method we have found deep levels responsible for the polarization of CdZnTe detector under high photon-fluxes. Identified deep levels ${{E}_{\text{v}}}+0.41$ eV, ${{E}_{\text{v}}}+0.77$ eV and ${{E}_{\text{v}}}+0.94$ eV can capture the photo-generated holes and thus form a positive space charge, which is responsible for polarization of the detector.

Copper oxide thin films are a topic of intense investigation by several researchers. Copper reacting with oxygen, depending upon the available energy, forms CuO, Cu₂O and Cu₄O₃ phases. Among these, Cu₄O₃ is a difficult phase to prepare. In the present communication, we report the preparation and properties of the stable phase of Cu₄O₃. These Cu₄O₃ thin films have been prepared at room temperature (300 K) on borosilicate glass by reactive DC magnetron sputtering. Cu₄O₃ thin films (of thickness 265  ±  5 nm) are p-type semiconductors (hole density 2.4  ×  10¹⁸ cc⁻¹ and Hall mobility 0.04 cm² V⁻¹ s⁻¹) and show a low resistivity (55 Ω cm). They have a direct band gap of 2.34 eV and an indirect band gap of 1.50 eV. The surface work function of Cu₄O₃ (measured by Kelvin Probe technique) is 5.35  ±  0.01 eV. Cu₄O₃ films are irradiated with laser radiation of 532 nm wavelength and 10 MW cm⁻² (120 s) power density. It shows a phase transformation to CuO which is confirmed by the Raman Spectroscopy measurements.

Strain-relaxation effects in AlN-buffered GaN/InGaN microdisks pivoted on Si posts of varying radii have been studied by micro-Raman spectroscopy and scanning near-field optical spectroscopy (SNOS). With increasing undercut beneath the microdisks by chemical wet-etching, the mitigation of biaxial tensile stress is found to be dependent on the contact areas between the Si posts and GaN microdisks. Strain-relaxation reduces the quantum-confined Stark effect (QCSE) in the quantum wells (QWs), leading to an 18.3% enhancement in InGaN QW internal quantum efficiency (IQE). Light out-coupling is also improved in the suspended regions owing to reduced optical absorption at AlN/Si interface compared to the central region. Meanwhile, spectral blue-shifts of ~45.6 meV are observed from the near-field photoluminescence (nf-PL) spectrum towards the edge of the microdisk. Such localization of strain relaxation can be exploited for precise strain engineering of the microdisks. The emission wavelengths of the microdisks can be stabilized by balancing strain-relaxation effects with thermal effects.

The effect of the annealing temperature on the light emission intensity of Tb-doped a-SiC:H thin films was investigated for different Tb concentrations under sub-bandgap photon excitation. We present a detailed discussion of rare-earth thermal activation in order to determine the optimal Tb concentration and annealing temperature for the highest Tb-related light emission intensity. Two independent processes that enhance the emission intensity are identified and incorporated in a rate equation. These are the thermally-induced increase of luminescence centers and the inhibition of host-mediated non-radiative recombinations. Finally, the presented analysis revealed a suppression of the self-quenching effect when increasing the annealing temperature.

We report polarization-controlled tunable rectifying behaviors in (K,Na)NbO₃ (KNN)/LaNiO₃ (LNO) heterostructures on silicon. The heterostructure shows a forward diode behavior at both the high resistance state and the low resistance state. The amplitude dependent rectifying features are attributed to the ferroelectric modulation effect on both the width of the depletion region and the height of the potential barrier at the KNN/LNO interface. By controlling the domain configurations using the writing voltage, the rectifying behaviors can be regulated and immediate states can be tuned. Our work shows the potential applications of KNN films in ferroelectric memristors.

We theoretically demonstrate a simple way to significantly enhance the spin/valley polarizations and tunneling magnetoresistnace (TMR) in a ferromagnetic-normal-ferromagnetic (FNF) silicene junction by applying a circularly polarized light in the off-resonant regime to the second ferromagnetic (FM) region. We show that the fully spin-polarized current can be realized in certain ranges of light intensity. Increasing the incident energy in the presence of light will induce a transition of perfect spin polarization from positive to negative or vice versa depending on the magnetic configuration (parallel or anti-parallel) of FNF junction. Additionally, under a circularly polarized light, valley polarization is very sensitive to electric field and the perfect valley polarization can be achieved even when staggered electric field is much smaller than exchange field. The most important result we would like to emphasize in this paper is that the perfect spin polarization and 100% TMR induced by a circularly polarized light are completely independent of barrier height in the normal region. Furthermore, the sign reversal of TMR can be observed when the polarized direction of light is changed. A condition for observing the 100% TMR is also reported. Our results are expected to be informative for real applications of a FNF silicene junction, especially in spintronics.

Although the Fano quantum interference of one longitudinal optical (LO) phonon mode and one electronic continuum of states due to inter-valence band transition has been investigated by the Raman spectra, there is no observation of the interference of multiple phonon modes despite its potential for electromagnetically induced transparency in the far infrared region. In this study, p-type Ga_0.5In_0.5P films with two main LO modes in the same plane of atomic vibration and one more mode due to CuPt-type ordering are investigated. Asymmetric line profiles, peak energy shifts and peak broadenings in the Raman spectra are analyzed, and the destructive quantum interference of these LO-continuum systems are observed. Discussion with the reference data of p-type GaAs and Si for the one-LO mode system reveals that the asymmetry parameter features the derivatives of the density of the continuum of states in the vicinity of the LO phonon energies and the degree of the electric polarization. It is found experimentally that the interaction between the two main LO modes through the interactions with the continuum states takes place. A₁(LO) mode due to the ordering affects the spectrum, however the interaction with the main two LO modes through the continuum is small. On the basis of the experimental result, the spectrum features for this alloy with greater hole density are estimated, where the various controls of the absorption spectrum in the phonon energy region are predicted.

We demonstrate the fabrication of shallow Si nanopillar structures at a submicron scale which provides broadband antireflection for crystalline Si (c-Si) solar cells in the wavelength range of 350 nm–1100 nm. The Si random nanopillars were made by reactive ion etch (RIE) processing with thermally dewetted Sn metals as an etch mask. The diameters and coverages of the Si nanopillars were adjusted in a wide range of the nanoscale to microscale by varying the nominal thickness of the Sn metals and subsequent annealing temperatures. The height of the nanopillars was controlled by the RIE process time. The optimal size of the nanopillars, which are 340 nm in diameter and 150 nm in height, leads to the lowest average reflectance of 3.6%. We showed that the power conversion efficiency of the c-Si solar cells could be enhanced with the incorporation of optimally designed Si random nanopillars from 13.3% to 14.0%. The fabrication scheme of the Si nanostructures we propose in this study would be a cost-effective and promising light trapping technique for efficient c-Si solar cells.

The electron attachment properties of octafluorotetrahydrofuran (c-C₄F₈O) are investigated using two complementary experimental setups. The attachment and ionization cross sections of c-C₄F₈O are measured using an electron beam experiment. The effective ionization rate coefficient, electron drift velocity and electron diffusion coefficient in c-C₄F₈O diluted to concentrations lower than 0.6% in the buffer gases N₂, CO₂ and Ar, are measured using a pulsed Townsend experiment. A kinetic model is proposed, which combines the results of the two experiments.

In this paper, we propose a new set of boundary conditions at ablative hot walls with thermionic electron emission for two-temperature thermal arc models in which the temperature of electrons can deviate from the temperature of heavy particles,$~{{T}_{\text{e}}}\ne {{T}_{\text{h}}}$. The boundary conditions are for the electric potential, the two energy equations for electrons and heavy particles (ions and neutrals), and the two mass conservation equations for the working gas and the vapour of the wall material. In these boundary conditions, the plasma sheath formed at the wall is viewed as the interface between the plasma and the wall, the plasma composition is assumed to be determined by a generalized Saha equation adapted to the case $~{{T}_{\text{e}}}\ne {{T}_{\text{h}}}$, and the reactive gas is assumed to form a stoichiometric film at the wall. The derived boundary conditions allow the calculation of the heat flux from the plasma to the wall, the thermionic electron current density, and the erosion rate of the wall that makes the model of wall–plasma interaction self-consistent. The derived boundary conditions are reduced to the case of non-reactive working gas and to the case of walls with materials with a low melting point, such as copper, where the thermionic electron emission of the wall is small and can be neglected. The case of the boundary conditions for high-pressure arcs burning in the vapour of the wall material (no working gas) is also considered. The boundary conditions obtained are applied to the cathode spot at an ablative tungsten cathode and to the anode attachment at a copper anode in argon.

A mode transition phenomenon was found in Hall thrusters, which was induced by the increase of the magnetic field gradient. In the transition process, we observed experimentally that there have been obvious changes in the oscillation, the mean value of the discharge current, the thrust, the anode efficiency, and the plume pattern. The shifting and compression of the high magnetic field causes the electron density in the discharge channel to decrease and the ionization zone to move towards the exit plane. This also corresponds to a low atom density in the discharge channel, resulting in a loss of stability of the ionization at a high magnetic field gradient, which presents the transition of the discharge mode.

A lightning channel attached to an aircraft in flight will be swept along the aircraft's surface in response to the relative velocity between the arc's root (attached to a moving electrode) and the bulk of the arc, which is stationary with respect to the air. During this process, the reattachment of the arc to new locations often occurs. The detailed description of this swept stroke is still at an early stage of research, and it entails the interaction between an electrical arc and the flow boundary layer. In this paper we examine the implications of the structure of the boundary layer for the arc sweeping and reattachment process by considering different velocity profiles, both for laminar and turbulent flow, as well as a high fidelity description, using large eddy simulation, of transitional flow over an airfoil. It is found that the local velocity fluctuations in a turbulent flow may be important contributors to the reattachment of the arc, through a combination of an increased potential drop along the arc and local approaches of the arc to the surface. Specific flow features, such as the presence of a laminar recirculation bubble, can also contribute to the possibility of reattachment.

TiO₂/Al₂O₃ nanolaminates are being investigated to obtain unique materials with chemical, physical, optical, electrical and mechanical properties for a broad range of applications that include electronic and energy storage devices. Here, we discuss the properties of TiO₂/Al₂O₃ nanolaminate structures constructed on silicon (1 0 0) and glass substrates using atomic layer deposition (ALD) by alternatively depositing a TiO₂ sublayer and Al₂O₃ partial-monolayer using TTIP–H₂O and TMA–H₂O precursors, respectively. The Al₂O₃ is formed by a single TMA–H₂O cycle, so it is a partial-monolayer because of steric hindrance of the precursors, while the TiO₂ sublayer is formed by several TTIP–H₂O cycles. Overall, each nanolaminate incorporates a certain number of Al₂O₃ partial-monolayers with this number varying from 10–90 in the TiO₂/Al₂O₃ nanolaminate grown during 2700 total reaction cycles of TiO₂ at a temperature of 250 °C. The fundamental properties of the TiO₂/Al₂O₃ nanolaminates, namely film thickness, chemical composition, microstructure and morphology were examined in order to better understand the influence of the number of Al₂O₃ partial-monolayers on the crystallization mechanism of TiO₂. In addition, some optical, electrical and mechanical properties were determined and correlated with fundamental characteristics. The results show clearly the effect of Al₂O₃ partial-monolayers as an internal barrier, which promotes structural inhomogeneity in the film and influences the fundamental properties of the nanolaminate. These properties are correlated with gas phase analysis that evidenced the poisoning effect of trimethylaluminum (TMA) pulse during the TiO₂ layer growth, perturbing the growth per cycle and consequently the overall film thickness. It was shown that the changes in the fundamental properties of TiO₂/Al₂O₃ nanolaminates had little influence on optical properties such as band gap and transmittance. However, in contrast, electrical properties as resistivity and mechanical properties as hardness and elastic modulus were shown to be very dependent. From these analyses, several applications could be suggested for different kinds of nanolaminates obtained in this work.

The diffusion mechanism of oxygen transport in the epitaxial La_0.7Sr_0.3MnO_3−δ films was examined for different practically significant conditions of annealing. An indirect method based on the interrelation between the phase transition temperature and the oxygen index was used for stepwise monitoring of the oxygen content in the film. Using a serial procedure of film annealing at different temperatures, we have revealed the abnormal behavior of diffusion transport of oxygen. The analysis of experimental data using numerical simulations demonstrates non-uniformity of the diffusion coefficient across the film thickness. The nature of the spatial dependence of the diffusion coefficient is associated with the lattice distortions of the film material.

We employ ab initio calculations to investigate energetics of point defects in metastable rocksalt cubic Ta-N and Mo-N. Our results reveal a strong tendency to off-stoichiometry, i.e. defected structures are surprisingly predicted to be more stable than perfect ones with $1:1$ metal-to-nitrogen stoichiometry. Despite the similarity of Ta-N and Mo-N systems in exhibiting this unusual behaviour, we also point out their crucial differences. While Ta-N significantly favours metal vacancies, Mo-N exhibits similar energies of formation regardless of the vacancy type (V_Mo, V_N) as long as their concentration is below $\approx 15~\text{at}. \%$. The overall lowest energies of formation were obtained for $\text{T}{{\text{a}}_{0.78}}\text{N}$ and $\text{M}{{\text{o}}_{0.91}}\text{N}$, which are hence predicted to be the most stable compositions. To account for various experimental conditions during synthesis, we further evaluated the phase stability as a function of chemical potential of individual species. The proposed phase diagrams reveal four stable compositions, $\text{M}{{\text{o}}_{0.84}}\text{N}$, $\text{M}{{\text{o}}_{0.91}}\text{N}$, $\text{Mo}{{\text{N}}_{0.69}}$ and $\text{Mo}{{\text{N}}_{0.44}}$, in the case of Mo-N and nine stable compositions in the case of Ta-N indicating the important role of metal under-stoichiometry, since $\text{T}{{\text{a}}_{0.75}}\text{N}$ and $\text{T}{{\text{a}}_{0.78}}\text{N}$ significantly dominate the diagram. This is particularly important for understanding and designing experiments using non-equilibrium deposition techniques. Finally, we discuss the role of defect ordering and estimate a cubic lattice parameter as a function of defect contents and put them in the context of existing literature theoretical and experimental data.

Transepithelial electrical resistance (TEER) measurements are regularly used in in vitro models to quantitatively evaluate the cell barrier function. Although it would be expected that TEER values obtained with the same cell type and experimental setup were comparable, values reported in the literature show a large dispersion for unclear reasons. This work highlights a possible error in a widely used formula to calculate the TEER, in which it may be erroneously assumed that the entire cell culture area contributes equally to the measurement. In this study, we have numerically calculated this error in some cell cultures previously reported. In particular, we evidence that some TEER measurements resulted in errors when measuring low TEERs, especially when using Transwell inserts 12 mm in diameter or microfluidic systems that have small chamber heights. To correct this error, we propose the use of a geometric correction factor (GCF) for calculating the TEER. In addition, we describe a simple method to determine the GCF of a particular measurement system, so that it can be applied retrospectively. We have also experimentally validated an interdigitated electrodes (IDE) configuration where the entire cell culture area contributes equally to the measurement, and it also implements minimal electrode coverage so that the cells can be visualized alongside TEER analysis.

A simple synthetic procedure for high-stable dispersions of porous composite Ag/AgCl nanoparticles stabilized with amphoteric surfactant sodium tallow amphopolycarboxyglycinate has been proposed for the first time. The prepared samples were characterized by UV–vis spectroscopy, x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy, small area electron diffraction (SAED), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and electron probe micro-analysis. In addition, measurements (carried out at the Kurchatov synchrotron radiation source stations) of the Ag K-edge extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) spectra and XRD of the prepared nanoparticles have been performed. The obtained results suggest that small-sized Ag clusters are homogeneously distributed in the mass of the AgCl nanoparticle (~80 nm) formed during the synthesis. The Ag/AgCl dispersion demonstrates photocatalytic activity (with respect to methyl orange) and high bactericidal activity against E. coli. This activity is superior to the activity of both Ag and AgCl nanoparticles stabilized by the same surfactant. Thus, porous composite Ag/AgCl nanoparticles can be used as a multifunctional agent that is able to remove both pollutants and bacterium from water.

Aluminum-doped cupric oxide (CuO:Al) was prepared via an out-diffusion process of Al from an Al-coated substrate into the deposited CuO thin film upon thermal treatment. The effect of the annealing temperature on the structural and optical properties of CuO:Al was investigated in detail. The influence of Al incorporation on the photovoltaic properties was then investigated by preparing a p-CuO:Al/n-Si heterojunction solar cell. A significant improvement in the performance of the solar cell was achieved by controlling the out-diffusion of Al. A novel in situ method to co-dope CuO with Al and titanium (Ti) has been proposed to demonstrate CuO-based solar cells with the front surface field (FSF) design. The FSF design was created by depositing a CuO:Al layer followed by a Ti-doped CuO (CuO:Ti) layer. This is the first successful experimental demonstration of the codoping of a CuO thin film and CuO thin film solar cells with the FSF design. The open circuit voltage (V_oc), short circuit current density (J_sc) and fill factor (FF) of the fabricated solar cells were significantly higher for the FSF device compared to devices without FSF. The FF of this device improved by 68% through the FSF design and a record efficiency ɳ of 2% was achieved. The improvement of the solar cell properties is mainly attributed to the reduction of surface recombination, which influences the charge carrier collection.