Multilayer nanolaminates (NLs) of alternate ultrathin sublayers of Al2O3 and TiO2 (ATA) with the thickness ranging ∼2 to 0.5 nm were fabricated by optimized pulsed laser deposition (PLD). Maxwell-Wagner (M-W) relaxation-induced interfacial polarization was realized and engineered by precisely controlling the sublayer thicknesses and the number of interfaces. X-ray reflectivity and cross-sectional transmission electron microscopy measurements of ATA NLs revealed an artificial periodicity with well-defined uniformly thick amorphous sublayers with chemically and physically distinct interfaces down to a sublayer thickness of ∼0.8 nm. The dielectric constants and loss of ATA NLs were found to increase from ∼60 to 670 and decrease from ∼0.9 to 0.16, respectively, as sublayer thicknesses reduced from ∼2 to 0.8 nm. However, for a sublayer thickness below 0.8 nm, the trend was reversed. Furthermore, temperature-dependent impedance spectroscopy studies revealed two distinct thermally activated relaxation processes, corresponding to TiO2 and Al2O3 sublayers, corroborating the M-W relaxation. The conductivity contrast between the sublayers of ATA NLs enhanced with reducing sublayer thickness and plateaued at a sublayer thickness of ∼0.8 nm, resulting in dominant M-W interfacial polarization and a high cut-off frequency of ∼50 kHz. These results demonstrate that ATA NLs grown by PLD may find application as potential high-k materials for next-generation nanoelectronic devices.

The present finding illuminates the physics of the formation of interfaces of metal based hetero-structures near layer continuous limit as an approach to develop high-efficiency W/B4C multilayer (ML) optics with ML periodicity varying d = 1.86-1.23 nm at a fixed number of layer pairs N = 400. The microstructure of metal layers is tailored near the onset of grain growth to control the surface density of grains resulting in small average sizes of grains to sub-nanometers. This generates concurrently desirable atomically sharp interfaces, high optical contrast, and desirable stress properties over a large number of periods, which have evidence through the developed ML optics. We demonstrate significantly high reflectivities of ML optics measured in the energy range 10-20 keV, except for d = 1.23 nm due to quasi-continuous layers. The reflectivities at soft gamma-rays are predicted.

Ceramic sample of CuCrO2 was synthesized via a solid-state reaction method. XANES, dielectric, ferroelectric, pyroelectric, synchrotron x-ray diffraction (SXRD), transmission electron microscope (TEM) and Raman measurements were performed on the prepared sample. Ferroelectric hysteresis loop, PUND, and pyroelectric current measurements indicate the presence of ferroelectricity in the prepared sample. The appearance of a broad maximum in dielectric permittivity and its frequency dispersion indicates the possibility of relaxor-type ferroelectricity in the system. Furthermore, TEM measurements revealed the presence of nano regions that are speculated to be polar and hence are giving rise to relaxor-type ferroelectricity. Careful analysis of XRD data indicates that the distorted CrO6 octahedra is giving rise to strain in the sample. This strain might be responsible for the observed nano regions, which might be polar, in the otherwise non-polar matrix. It is proposed that these polar regions are responsible for the presence of relaxor-type ferroelectricity in the sample.

a-SiNx:H thin films of different stoichiometry grown by PECVD were subjected to irradiation by 100 MeV Au8+ ions with various fluences to understand the effect of stoichiometry on properties of thin films upon irradiation. Ellipsometry and UV-Vis study suggest the variation in the refractive index of thin films with fluence. The evolution of Hydrogen due to irradiation is quantified with the help of ERDA. RBS was probed to study the change in thin films' composition upon irradiation, which further helps understand the change in thin films' optical properties. Quenching of photoluminescence in the films with all stoichiometries was also observed due to ion irradiation. X-TEM images show the formation of discontinuous ion tracks of radius 2.5 nm in the film closer to silicon nitride stoichiometry. However, Si rich film does not show the clear formation of tracks. Results are explained in the framework of the Thermal spike mechanism of ion-solid interaction.

5 Arindam Majhi1,2, Maheswar Nayak1,2*, Paresh Chandra Pradhan3, Suvendu Jena4, Anil 6 Gome5, Manvendra Narayan Singh1, Himanshu Srivastava1, Varimalla Raghvendra Reddy5, 7 Arvind Kumar Srivastava1,2, Anil Kumar Sinha1,2, Dinesh Venkatesh Udupa2,4 and Ullrich 8 Pietsch6 9 10 1Synchrotrons Utilization Section, Raja Ramanna Centre for Advanced Technology, Indore 11 452013, India 12 2Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India 13 3 Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA 14 4Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, 15 India 16 5UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 17 452001, India 18 6Universität Siegen, Walter-Flex-Strasse 3, Siegen, 57072, Germany 19 20 *Corresponding author: mnayak@rrcat.gov.in 21 22 23

This work reports the correlation of changes in structural and optical properties of a-SiNx:H thin films irradiated with 100 MeV Au8+ at various fluences. Cross-sectional TEM studies show the evolution of discontinuous ion tracks with a radius of 3 nm as the nanoscale structural changes in films. Spectroscopic ellipsometry was used for the extraction of different optical parameters, viz., refractive index, extinction coefficient, Urbach tail energy, and bandgap along with thickness and roughness by fitting the experimental data and modeling the dielectric function with the Cody–Lorentz model. An increase in the Si-N phase was evident, with an increase in the bandgap. Change in the Urbach energy and broadening of oscillator parameters suggest an increased disorder and introduction of defect states upon irradiation. The Wemple–Dedomenico dispersion model was used to deduce dispersion energy to establish a change in thin films' density upon irradiation. The change in the density of thin films is further correlated to the increase in the refractive index. The evolution of various parameters reveals the correlation between changes in optical properties with structural properties down to nanoscale upon swift heavy ion irradiation on a-SiNx:H thin films.

Micro-Faraday cup array (MFCA) detectors are used for the detection and analysis of incident ion particles with greater stability and precision.New and simple micro FCA structures have been designed and fabricated considering the application in mass spectrometry and laser plasma techniques.MFCA structures were fabricated using UV lithography followed by deep reactive ion etching (DRIE).The UV lithography process was utilised for fabrication of micro-Faraday cup array structure in photoresist (AZ4903) deposited on n-type silicon substrate.After that DRIE process was used for creating array pattern in silicon.Ultimately 1 × 16 arrays having 25 µm widths with 125 µm spacing were fabricated.Maximum depth achieved with DRIE process was 16 µm.Exposure time of lithography was found to be reduced by 110% using UV-LED source for these structures.Effects of etch cycle time on cup depth and sidewall angle have also been discussed.

This paper presents investigated results of copper-oxide nanowires used as a humidity sensor. Copper-oxide nanowires films were grown over cross-comb type gold electrodes on a SiO2 substrate using thermal annealing technique, and its humidity sensitive characteristics were investigated through resistance across the gold electrodes. These copper-oxide nanowires films revealed high sensitivity and long-term stability with fast response time. It was found that resistance across gold electrodes of the fabricated sensor decreases with increase in humidity almost linearly on a logarithmic scale. It appears that copper-oxide nanowires can be used as low-cost humidity sensor with high output reliability and reproduction rate. The observations were carried out at room temperature (RT) and relative humidity (RH) in the range of 6% to 97%.

The structural, microstructural, local ordering of B-site cations, dielectric and ferroelectric properties have been investigated for Pb1-xGdx(Mg1/3Nb2/3)(1-x/4)O-3; 0 <= x <= 0.1. Charge imbalance due to Gd3+ ion substitution at Pb2+ is compensated by creating B-site vacancies. The Gd-ion doping at Pb sites in PMN results in the formation of a secondary GdNbO4 phase, which is explained by considering the ionic radii of the Gd ion and its solubility limit at Pb-ion sites. A reaction mechanism for the formation of GdNbO4 has been proposed. Selected area electron diffraction along the < 110 > axis reveals enhancement in size of the non-stoichiometric chemical ordered regions leading to a decrease in the size of polar nano regions and their correlations, which manifests in a decrease of T-m, a more diffused epsilon(max) peak and enhancement of the dielectric relaxation strength calculated from fitting of the frequency and temperature dependence of the dielectric behavior. Linear dependence between polarization and electric field also signifies reduction in the correlation between the PNRs resulting in the decrease of the value of P-max (at similar to 30 kV cm(-1)).

Silicon-rich silicon nitride (SRSN) films having two different compositions were irradiated with 100 MeV of Ni7+ ions at fluences of 5 × 1012 ions/cm2 and 1 × 1014 ions/cm2. The films, despite having different compositions, showed similar microstructural evolution, as evidenced in cross-sectional transmission electron microscopy (XTEM). Discontinuous tracks (~2 nm wide) appeared under a fluence of 5 × 1012 ions/cm2, and they overlapped and dissolved at an increased fluence of 1 × 1014 ions/cm2. The corresponding changes in photoluminescence (PL) of the films were investigated with three lasers with the aim of tracking the evolution of different radiative processes in SRSN with ion fluence. The evolution of PL with fluence was well correlated with microstructural evolution. PL results showed that ion irradiation progressively leads to the simultaneous creation of both radiative and non-radiative defects, with the latter dominating at higher fluences. The results are understood on the basis of a thermal spike model of ion–materials interaction.

We have used simple chemical bath deposition technique to grow nearly monodispersive CdS nanocrystals in PVP matrix. Systematic study of variation of growth parameters has revealed that optimized growth of CdS nanocrystals in PVP matrix depends on relative concentration of Cd acetate/Thiourea to polyvinyl pyrrolidone in the bath. It is also observed that higher concentration (1M) of Cd acetate/Thiourea gives rise to smaller NCs compared to lower concentration (0.5M), however density of particles is large in thin film grown using 1M concentration. Scanning electron microscopic studies show that it is a nanoparticulate film of spheres of size around 100-200nm. Further, absorption, energy dispersive spectroscopy and transmission electron microscopic investigations reveal that nearly monodispersive CdS nanocrystals are embedded in 100-200 nm PVP spheres for the range 0.5 M, 1M Cd acetate/Thiourea concentration (figure 1). The effect of varying PVP, Cd acetate/Thiourea concentration, sequence and addition of ingredients and heating/cooling cycles have been studied and results are corroborated with existing theory.