Glancing Angle Research Articles

Indium Nanoparticles Capped TiO₂ Nanowire Array for Boosted Photosensing Adoption

The boosted photosensing performances have been reported for Indium (In) nanoparticles (NPs) capped TiO2 nanowire (NW) array using Glancing angle deposition (GLAD) technique. The In NP based photosensor possessed high ideality factor of ~12.8 and the enhancement in photoresponsivity has been also observed. The ON/OFF switching irradiation for the In NPs based photosensor has increased from $4.6~\mu \text{A}$ to $6.2~\mu \text{A}$ and vice versa with a rise time of 0.45 sec and fall time of 0.56 sec.

Bandgap Modulation of Glancing Angle Deposition Aided Ag Nanoparticles Covered TiO₂ Thin Film by High Temperature Annealing.

Glancing Angle Deposition (GLAD) technique has been used to fabricate the Ag nanoparticles (NPs) over TiO₂ thin film (TF) on the n-Si substrate. The deposited Ag NPs are in the size of 3-5 nm. Open-air annealing has been done at 500 °C and 600 °C for the n-Si/TiO₂ TF/Ag NP samples. High Resolution X-ray Diffraction (HRXRD) peaks were identified to calculate the crystalline size of the NPs and rutile phase of the annealed sample were exhibited. Morphological analysis has been done for the sample using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS) and Atomic Force Microscopy (AFM). The enhancement of plasmonic absorption and modulation in the bandgap for the annealed Ag NPs surrounded TiO₂ TF has been verified by UV-Vis Spectroscopy and the bandgap has been calculated using Tauc plot. An overall 2.5 fold and 3 fold enhancement has been observed in the UV region and visible region for n-Si/TiO₂ TF/Ag NP annealed at 500 °C and 600 °C samples as compared to the n-Si/TiO₂ TF/Ag NP as-deposited samples. The modulation of bandgap due to the sub-band transition and Localized Surface Plasmon Resonance (LSPR) effect of Ag NPs and relevant sub-band transition due to change in annealing temperature has been reported.

High Sensitivity and Selectivity of Array Gas Sensor through Glancing Angle Deposition Method

In this study, we propose an array-type gas sensor with high selectivity and response using multiple oxide semiconductors. The sensor array was composed of SnO2 and In2O3, and the detection characteristics were improved by using Pt, Au, and Pd catalysts. All samples were deposited directly on the Pt interdigitated electrode (IDE) through the e-beam evaporator glancing angle deposition (GAD) method. They grew in the form of well-aligned nanorods at off-axis angles. The prepared SnO2 and In2O3 nanorod samples were exposed to CH3COCH3, C7H8, and NO2 gases in a 300℃ dry condition. Au-decorated SnO2, Au-decorated In2O3, and Pd-decorated In2O3 exhibited high selectivity for CH3COCH3, C7H8, and NO2, respectively. They demonstrated a high detection limit of the sub ppb level computationally. In addition, measurements from each sensor were executed in the 40% relative humidity condition. Although there was a slight reduction in detection response, high selectivity and distinguishable detection characteristics were confirmed

Detection of subassembly bowing in a fast breeder reactor using glancing angle ultrasonic imaging

Mapping of subassembly (SA) heads using down viewing transducers mounted on an under sodium ultrasonic scanner can be used for detection and evaluation of SA bowing. However, due to constraints in the rotating plugs on which the scanner is mounted, the down viewing transducers may not reach on top of all the SAs. For such a scenario, an ultrasonic glancing angle based imaging methodology (GAIM) is developed in the present paper for assessment of SA bowing. The signatures in the ultrasonic signals that can be used for detection of SA head bowing (towards or away) with respect to the ultrasonic transducer are reported in this paper. In addition to the detection of the SA bowing, glancing angle images from two orientations are superimposed to get a better visualization of the honeycomb arrangement of SAs. Further, a method for quantitative estimation of the bowing is also presented.

Scrutinizing and Collating the Broadband Photo-Detection Properties of Isotype n-MnO₂/TiO₂ Nanostructure

Fabrication of heterostructure MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin film (TF) and MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanowires (NW) has been carried out using Glancing angle deposition technique. The X-ray diffraction pattern revealed MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are crystalline, while TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are amorphous in nature. Formation of the vertically aligned NW can further be verified from field emission gun scanning electron microscopy. The fabricated NW shows 15-fold enhancement in UV-Vis absorption. Detectivity was found out to be 9.9 × 1010 Jones and 1.95 × 1012 Jones for MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> TF and MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> NW respectively. The calculated NEP is 4.2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-11</sup> W for MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> TF and 2.1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> W for MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> NW. This indicates the overall improved noise performance by MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ITiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> NW. The rise and fall time of NW are 0.21 s and 0.50 s respectively, which is faster compared to 0.29 s and 0.64 s of TF. In overall, NWs shows great performance as compared to TF and has a great potential in applications of uv-vis range photodetector.

Elastic behavior of anisotropic coatings sputter-deposited at oblique incidence

In this work, the elasticity constants of anisotropic thin films were determined using a model developed specifically in order to use the Impulse Excitation Technique (IET). The model is based on the lamination theory and was validated with a finite element analysis. The IET was used in flexural and torsional vibration modes in order to determine the Young's and shear moduli of coatings. The anisotropic behavior was evaluated for titanium thin films deposited by magnetron sputtering at Glancing Angle Deposition (GLAD) on glass substrates and silicon wafers. The elastic response was examined for three different glancing angles and the presence of in-plane anisotropy of the film was noticed from the measured elasticity constants. The difference between conventional and GLAD sputtering was evaluated in terms of microstructure, texture evolution and elastic properties. The influence of the film porosity on the elasticity constants was investigated. Nanoindentation measurements were performed in order to evaluate the effect of the glancing angle on the hardness and the reduced modulus. The results revealed that the elasticity constants of the titanium thin film were mostly affected by the glancing angle and they decreased when the glancing angle increased. The same effect was noticed for the film hardness and reduced modulus. Upon increasing the glancing angle, the film anisotropy was increased owing to different factors, among which the non-standard columnar growth and the inclined crystallites toward the vapor flux direction.

Nitrogen-Enriched Cr1-xAlxN Multilayer-Like Coatings Manufactured by Dynamic Glancing Angle Direct Current Magnetron Sputtering.

Multilayer-like CrN and Cr1−xAlxN coatings with different Al contents were deposited onto a stainless steel substrate using dynamic glancing angle deposition direct current magnetron sputtering (DGLAD dcMS) in a N rich atmosphere to understand the role of Al on the growth of the films and mechanical properties of the nitrides with a multilayer architecture. Chemical analysis by means of energy dispersive analysis (EDS) and glow discharge optical emission spectroscopy (GDOES) depth profiling revealed that while CrN samples were close to stoichiometric, the Cr1−xAlxN coatings presented excess N between 70 and 80% at. An expressive change in texture was observed as the CrN coating changed its preferred orientation from (111) to (200) with the addition of Al, followed by a modification in morphology from grains with faceted pyramidal tops in CrN to dome-shaped grains in Cr1−xAlxN coatings. Multilayer-like nanostructures of corrugated grains were produced with a periodicity of approximately 30 nm using dynamic glancing angle deposition. The deposition rate was drastically reduced with an increase of Al, meanwhile, the best mechanical performance was achieved for the coating with a higher content of Al, with hardness up to 27 GPa and a higher value of maximum resistance to plastic deformation.

Grazing-incidence X-ray diffraction investigation of the coincidence site lattice of the Ge/Si(001) system.

The Ge/Si(001) system has been analysed by grazing-incidence X-ray diffraction on a standard laboratory X-ray diffraction tool. A periodic array of interfacial edge dislocations forms a coincidence site lattice (CSL) which yields equidistantly spaced satellite peaks close to Bragg peaks of the Ge layer and Si substrate. The diffraction behaviour of the CSL was analysed using 2θ/φ scans along [100], [110] and [310] directions as well as azimuthal φ scans which revealed a 90° angular symmetry of the CSL. Additionally, different layer thicknesses, from 10 to 580 nm, were analysed, focusing on the dependence of layer thickness on the glancing angles of the satellite peaks. This method provides the ability to analyse whether or not epitaxially grown layers exhibit a periodic array of dislocations, and gain information about the orientation of the interfacial edge dislocations.

Glancing Angle Deposition and Growth Mechanism of Inclined AlN Nanostructures Using Reactive Magnetron Sputtering

Glancing angle deposition (GLAD) of AlN nanostructures was performed at room temperature by reactive magnetron sputtering in a mixed gas atmosphere of Ar and N2. The growth behavior of nanostructures shows strong dependence on the total working pressure and angle of incoming flux. In GLAD configuration, the morphology changed from coalesced, vertical nanocolumns with faceted terminations to highly inclined, fan-like, layered nanostructures (up to 38°); while column lengths decreased from around 1743 to 1068 nm with decreasing pressure from 10 to 1.5 mTorr, respectively. This indicates a change in the dominant growth mechanism from ambient flux dependent deposition to directional ballistic shadowing deposition with decreasing working pressures, which is associated with the change of energy and incident angle of incoming reactive species. These results were corroborated using simulation of metal transport (SiMTra) simulations performed at similar working pressures using Ar and N separately, which showed the average particle energy and average angle of incidence decreased while the total average scattering angle of the metal flux arriving at substrate increased with increasing working pressures. Observing the crystalline orientation of GLAD deposited wurtzite AlN nanocolumns using X-ray diffraction (XRD), pole-figure measurements revealed c-axis &lt;0001&gt; growth towards the direction of incoming flux and a transition from fiber-like to biaxial texture took place with increasing working pressures. Under normal deposition conditions, AlN layer morphology changed from {0001} to {101¯1} with increasing working pressure because of kinetic energy-driven growth.

An experimental and theoretical understanding of a UV photodetector based on Ag nanoparticles decorated Er-doped TiO2 thin film

Glancing angle deposition (GLAD) was employed to synthesise plasmonic Silver (Ag) nanoparticles (NPs) on the chemically prepared Erbium-doped Titanium dioxide (Er:TiO2) thin films (TFs). The impact of using Ag NPs on the morphological, optical, and electrical aspects of Er:TiO2 TFs were sequentially analysed. From the field emission scanning electron microscopy (FESEM) image, the Ag NPs appeared spherical and uniformly distributed on the Er:TiO2 TFs. The size (diameter) of the maximum number of Ag NPs was ~15 nm (calculated from FESEM image). Energy dispersive X-ray (EDX) spectra assured the presence of Ag NPs on the TFs. X-ray diffraction (XRD) pattern for Ag NPs decorated Er:TiO2 TFs closely resembled the face centred cubic crystal structure of Ag NPs and body centred tetragonal Ag–O compound. The optical spectroscopy (UV–visible diffuse reflectance and photoluminescence) elucidated that the absorption of light was significantly enhanced in the UV–visible spectral range for the TFs in which Ag NPs were sandwiched between Er:TiO2 TF layers (Er:TiO2/Ag NPs/Er:TiO2). The Schottky contact-based Au/Er:TiO2/Si photodetector (PD) and Au/Er:TiO2/Ag NPs/Er:TiO2/Si (plasmonic) PD were constructed. The plasmonic PD offered a better photo-responsivity of ~4.5 fold higher as compared to Er:TiO2 TF-based PD upon 380 nm illumination under −6 V bias. An increase in detectivity and a decrease in noise equivalent power was observed for the plasmonic device compared to Er:TiO2 device in the UV region. A theoretical approach had been adopted to calculate the wavelength-dependent responsivity for both devices. Further, the important parameters like photoconductive gain, electron transit time and electron mobility were calculated by simulating the experimental responsivity curves of the devices. These parameters exhibited improvement in the UV regime for the plasmonic PD. The fast temporal response with short rise and decay time proves the excellent efficiency of the plasmonic UV PD.

Highly improved responsivity of self-powered UV–Visible photodetector based on TiO2/Ag/TiO2 multilayer deposited by GLAD technique: Effects of oriented columns and nano-sculptured surface

The outstanding progress made in optoelectronic technologies calls for a renewed performance assessment of photodetectors (PDs) for next-generation sensing applications. Here, TiO2/Ag/TiO2 tri-layered films were sputtered using the GLancing Angle Deposition (GLAD) technique in which the deposition angle was varied from 0 to 80°. Before the elaboration, a strategic combination of Genetic Algorithm (GA) and numerical analysis was used to find out the best multilayer geometry offering superior optical performance. The influence of the inclined architecture on the performance of the prepared TiO2/Ag/TiO2 multilayer was analyzed. Optical characterization reveals that near-perfect UV photodetection and over than 60% of visible-absorbance were achieved by taking a deposition angle of 80°. These enhancements are correlated to the surface nano-sculptured structures, which gives rise to an enhanced light-trapping capability. The measured I-V curves of the obliquely-deposited structures showed a clear photovoltaic mode and an extremely low dark current of a few picoamperes. Besides, the devices demonstrate an enhanced self-powered UV–Vis photoresponse, yielding superb UV and visible responsivity of 0.2A/W and 47 mA/W, respectively. The UV, blue, and green current ratios were respectively 137, 113, and 107 dB. Therefore, promoting efficient light management, this innovative concept of inclined tri-layer films provides a sound pathway for designing potential alternative self-powered UV–Vis PDs appropriate for the future development of the optoelectronic technology.

Magnetic Response Dependence of ZnO Based Thin Films on Ag Doping and Processing Architecture.

Multifunctional and multiresponsive thin films are playing an increasing role in modern technology. This work reports a study on the magnetic properties of ZnO and Ag-doped ZnO semiconducting films prepared with a zigzag-like columnar architecture and their correlation with the processing conditions. The films were grown through Glancing Angle Deposition (GLAD) co-sputtering technique to improve the induced ferromagnetism at room temperature. Structural and morphological characterizations have been performed and correlated with the paramagnetic resonance measurements, which demonstrate the existence of vacancies in both as-cast and annealed films. The magnetic measurements reveal changes in the magnetic order of both ZnO and Ag-doped ZnO films with increasing temperature, showing an evolution from a paramagnetic (at low temperature) to a diamagnetic behavior (at room temperature). Further, the room temperature magnetic properties indicate a ferromagnetic order even for the un-doped ZnO film. The results open new perspectives for the development of multifunctional ZnO semiconductors, the GLAD co-sputtering technique enables the control of the magnetic response, even in the un-doped semiconductor materials.

Au Nanospirals Transferred onto PDMS Film Exhibiting Circular Dichroism at Visible Wavelengths.

We propose a thin, single-layered circular dichroic filter with Au nanospiral structures on a polydimethylsiloxane (PDMS) thin film that has strong circular dichroism at visible wavelengths. Au nanospiral structures with a diameter of 70 nm were fabricated by cryogenic glancing angle deposition on a substrate with a nanodot array template patterned with the block copolymer PS-PDMS. The Au nanospiral structures were transferred onto a transparent and flexible PDMS thin film to fabricate a thin, single-layered circular dichroic filter. The filter had a very large circular dichroism peak of −830 mdeg at 630 nm. The results show that the Au nanospiral structures transferred onto PDMS thin film exhibit large circular dichroism at visible wavelengths.

Wetting Properties of Transparent Anatase/Rutile Mixed Phase Glancing Angle Magnetron Sputtered Nano-TiO2 Films.

Transparent polycrystalline TiO2 thin films have been deposited on unheated glass substrates using RF reactive magnetron sputtering. Depositions were carried out at different glancing angles and with different total gas mixture pressures. The variation of these parameters affected the crystal phase composition and the surface morphology. Depending on the glancing angle and the pressure, rutile, mixed anatase/ rutile and pure anatase were deposited at low substrate temperature. Both hydrophilic and hydrophobic TiO2 were obtained, exhibiting fast photoconversion to superhydrophilic upon UV irradiation. The effect of the materials physicochemical properties on the wettability and rate of the UV induced superhydrophilicity is evaluated.

Influence of the sputtering glancing angle on the microstructure and adsorption characteristics of Zr-Co-RE getter films

Zr-Co-RE non-evaporable getter films have excellent gas adsorption performance therefore can be used in vacuum sealed electronic devices. The microstructure of getter films has vital effect on adsorption performance. In this paper, Zr-Co-RE films deposited by DC magnetron sputtering at different glancing angles are investigated including microstructures and adsorption characteristics. The surface and cross-sectional morphologies demonstrate loose, porous and columnar-like structure which forms because of low lateral mobility of Zr and Co atoms and shadowing effect of non-perpendicular sputtering. Zr-Co-RE films are amorphous or nanocrystalline structure. The films deposited at 90° glancing angle show large grain size. After Zr-Co-RE films are heated at 350 °C for 15 min, the H2 adsorption capacity and pumping speed at ambient temperature are tested. The films grown at 90° glancing angle have highest initial pumping speed (103.9 ml s−1 cm−2), which owe to its more gas diffusion path and active surface, meanwhile, the adsorption capacity is lower than 60° because of difficult and limited diffusion process into getter matrix. The films grown at 60° glancing angle have best adsorption capacity (71.5 Pa.ml cm−2) and pumping speed stability.

Morphological characterization and porosity profiles of tantalum glancing-angle-deposited thin films

Abstract. Glancing angle deposition (GLAD) is a physical vapor deposition (PVD) process using a substrate that rotates tilted at an angle to the evaporation source. Depending on the deposition conditions, it provides the controlled formation of regular nanostructures during the PVD process. As a result, a wide variety of shapes, such as spirals or vertical columns, can be easily fabricated in the nanometer range. For this reason, GLAD has already been proven reliable in the production of optical coatings with very low reflectance in a broad spectral range. This paper examines the morphology of tantalum nanostructures deposited on planar silicon substrates by electron beam evaporation. The prepared samples are characterized by scanning electron microscope (SEM) images at a breaking edge with respect to the layer structure and by focused ion beam (FIB) SEM images of the cross-sectional areas with respect to the porosity. The porosity can be used to model the optical properties of the thin film with the effective medium theory (EMT). Our work studies the relationship between the evaporation parameters (growth pitch and deposition angle) and thin film morphology of tantalum so that in future work the optical properties can be linked to the deposition parameters, which in turn can be chosen to achieve highly absorbent infrared radiation layers, e.g., for infrared sensors. It was shown that the porosity across the film thickness of both columnar and screw-like thin films is nearly constant, whereas the porosity profiles of spiral structures show a periodic pattern, the period of which seems to depend on the growth pitch.

Design of $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructures using glancing angle deposition technique for enhanced photodetection

Glancing angle deposition technique was employed to fabricate $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure on n-type Si substrate. The X-ray diffraction analysis depicts that the $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was polycrystalline in nature. Higher photoluminescence intensity was obtained for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure as compared to bare $$\text {SnO}_{2}$$ nanowires, due to the higher junction area between two layers and higher electron–hole pair generation. The photodetectors fabricated using $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure showed averagely 2.3 times higher photoresponse as compared to bare $$\text {SnO}_{2}$$ nanowire photodetector at $$-2$$ V. The enhanced photoresponse for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was described with reference to the interface junction. A high responsivity of 16.43 A/W and high detectivity of $${2.58}\times {10}^{{12}}$$ jones with noise equivalent power as low as $${1.085}\times {10}^{-12}$$ W were obtained for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure. Moreover, the current conduction mechanism of $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was explained with the help of the band diagram.

Through-Thickness Strain Gradient in a Hot-Rolled Al-Mg Alloy Obtained by Nanoindentation and Glancing Angle X-Ray Diffraction

Combined nanoindentation and glancing angle X-ray diffraction (GAXD) methods were used to study the mechanical properties of near-surface microstructures (NSMs) of a hot-rolled 5xxx aluminum alloy. Nanoindentations with a sharp indenter were carried out with penetration depth ranging from 250 nm to 4500 nm at the near-surface regions as well as the bulk of the hot-rolled alloy. The primary indentation parameter presented here was the hardness, given that plastic strain obtained from GAXD experiment could be correlated with the hardness value. Analysis of nanoindentation hardness results proved that NSMs of this alloy on average were harder than the bulk due to the presence of different surface features discussed here. The GAXD experiments were performed between a minimum incident angle 0.025°, equivalent to 765 nm penetration depth, and a maximum angle 1°, equivalent to 3000 nm penetration depth. The strain-induced broadening in the diffraction peaks was calculated by the Williamson–Hall technique. Both indentation hardness and glancing angle diffraction results confirmed strain gradient as a function of depth in the NSMs of the alloy. Both techniques also showed that the thickness of the subsurface layer (i.e., several micrometers below the surface) of hot-rolled sample was approximately 2.44 μm at the tested areas. Additionally, reported results provided evidence for the ability to use glancing angle X-ray diffraction as a nondestructive tool for the measurement of subsurface layers' thickness as well as microstrain (non-uniform or plastic strain) as a function of depth.

Rear‐Passivated Ultrathin Cu(In,Ga)Se2 Films by Al2O3 Nanostructures Using Glancing Angle Deposition Toward Photovoltaic Devices with Enhanced Efficiency

AbstractIn this work, for the first time, the addition of aluminum oxide nanostructures (Al2O3 NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se2 device (400 nm) fabricated using a sequential process, i.e., post‐selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al2O3 NSs with improved Se diffusion into the non‐uniformed metallic precursor due to the surface roughness resulting from the Al2O3 NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al2O3 NSs. The coverage and thickness of the Al2O3 NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na2SeX and phase separation. The passivation effect attributed to the Al2O3 NSs is well studied using the bias‐EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al2O3 NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se2 devices, and providing significant opportunities for further applications.

Corrosion protection of steel substrates by magnetron sputtered TiMgN hard coatings: Influence of surface morphology and Mg content on Mg release in NaCl solutions

TiMgN coatings with three different Mg contents (10, 20 and 35 at.%) were prepared by reactive magnetron co-sputtering. Three different coating microstructures have been studied by using i) polished and ii) sand-blasted sample surfaces and iii) by employing the Glancing angle deposition (GLAD) technique on polished substrates. The chemical composition was analyzed by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry or by glow discharge optical emission spectrometry and coating morphology was characterized by SEM on focused ion beam sliced samples. To determine the Mg release from the TiMgN samples two techniques measuring the open circuit potential were employed: a) an in-situ technique by using a scanning flow cell coupled to an inductively coupled plasma mass spectrometer and b) an ex-situ technique, namely inductively coupled plasma optical emission spectroscopy. The results (measured Mg release) from these two analysis techniques are compared and discussed with respect to results obtained from corrosion studies performed in neutral salt spray tests. It was found that the lowest Mg release has been determined for polished and the highest for GLAD samples. A correlation between the amount and duration of Mg release with the corrosion behavior of the samples could be established and formerly proposed corrosion protection mechanisms could be confirmed.