Thin film filed effect transistors (TFTs) have drawn significant attention from scientific community as one of the most attractive for low-cost, large area and flexible electronics.In this context, the development of high-k dielectric materials with additional functional properties is essential for low voltage operating and enhancement of device performance. This work presents the investigation of solution processed Pb(Zn1/3Nb2/3)O3 4.5PbTiO3(PZN PT) perovskite nanoparticles thin films, with and without Mn doping, as gate dielectrics for thin film transistor applications. PZN-PT with 1% Mn doped and undoped PZN-PT films were deposited by spin coating on nanostructured doped n-type silicon substrate to form metal-oxide-semiconductor (MOS) structures with top silver contact. SEM analysis shows Mn doping PZN-PT presents a denser and more homogeneous microstructure compared to undoped. Electrical measurements confirmed transistor operating mode and highlighted the effect of ferroelectric polarization on device behavior.

Despite the excellent properties of Pb(Zn1/3Nb2/3)O-3-4.5PbTiO(3) (PZN-4.5PT) single crystals, the greatest difficulty for their application on electronic devices is to make them to thin layers related to the difficulty to make them as ceramic materials. In this paper, we use the combined USAXS/SAXS/WAXS instrument at 9ID beamline at APS-ANL for in situ characterization of PZN-4.5PT inorganic perovskite nanoparticles thin films deposited on nanotextured silicon to understand the phase transitions and determine the observed microcrystals' structure. The sample was annealed from ambient to 1000 degrees C. The results revealed structure changes in the nanoparticles' thin films which could be explained by the new phase that can be assigned to the Pb-3(PO4)2-based component. The peak at 31 degrees indicates the presence of the rhombohedral phase perovskites assigned to the nanoparticles. WAXS characterization permitted to identification of many transitions during thermal annealing like dehydration or dihydroxylation of phosphorus gel -OH bonds and internal water.

In this study, we investigate the influence of solvents with different boiling points on the electrical performances of poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) transistors. To dissolve PBTTT for thin-film processing, we used toluene, chlorobenzene (CB), and tetrahydrofuran (THF). The highest obtained field effect mobilities were about 3.42 × 10−2 cm2 V−1 s−1, 1.62 × 10–3 cm2 V−1 s−1, and 1.78 × 10–2 cm2 V−1 s−1, respectively, for PBTTT devices using chlorobenzene, toluene, and tetrahydrofuran and heated respectively at 120 °C, 150 °C, and 120 °C. In order to point out the role of morphological properties, AFM images were performed. We observed liquid crystalline state formation in PBTTT film from THF and toluene which drive the electrical parameters over grain size.

The idea to use ferroelectric materials (PZN-PT) came from the fact that the ferroelectric nature could facilitate electric charges accumulation on the interfaces of the solar cell. Thus, it would increase the open circuit voltage Voc which could reach more than 10 V. This would directly impact the efficiency which is proportional to Voc, thus hoping to obtain solar efficiency never equaled by the halide perovskites which are less stable and less resistant in aggressive environments. In this work, the solar cells produced gave an exceptional record efficiency of 39.32% with a very high open circuit voltage (Voc) of 3.50 V, a short-circuit current density (Jsc) of 0.118 mA/cm2 and an FF of 0.72 measured in the positive polarization direction under 3825 lux (5.6 W/m2) lighting. The negative polarization direction under 4781 lux (7 W/m2) lightning gave a current density of 2 mA/cm2, an open circuit voltage of 2.30 V and an FF of 0.35.

The ideal band gap for a photovoltaic active layer for the solar spectrum is around 1.3 eV. However oxides with such values are rare. One of the most studied oxides to date as a photovoltaic active layer is the cuprous oxide Cu2O. Its band gap is around 2.1 eV and is therefore not ideal for the solar spectrum. Power Conversion Efficiency generally do not exceed 4 we propose to study an emerging type of solar cell that is based on ferroelectricity. In this type of solar cell, a p-n junction is not necessarily required, unlike conventional solar cells. Interesting conversion efficiencies are beginning to be obtained with this type of cell, however the mechanisms are still not well understood and several material and engineering challenges must be addressed. The objective of this paper is to initiate an innovative photovoltaic technology based on novel inorganic with suitable bandgap widths and organic materials (biopolymer). These oxides are more stables. We synthesized ferroelectric materials that absorb a large part of the solar spectrum with reduced bandgap widths. PZN-4.5PT nanoparticles were dispersed in a biopolymer matrix. Hybrid thin films with these inorganic nanoparticles embedded in a biopolymer have been successfully fabricated by spin coating on ITO substrate. Structural, morphological and electrical properties were investigated. The best Power Conversion Efficiencies measure under a light LED illumination of 3550 lux are respectively 21.83 light exposition with an open-circuit voltage of 5.17 and 5.86 V.

The Pb(Zn 1/3 Nb 2/3 )O3-4.5PbTiO 3 (PZN-4.5PT) single crystals showed very large ferroelectric and piezoelectric properties compared to traditional ferroelectric ceramics (BaTiO 3 and PZT) used presently as active material in medical imaging, detection and sonars. However, despite these excellent properties, the greatest difficulty to use PZN-4.5PT single crystals on electronic devices is to achieve them in thin layers form because of their incongruent melting property. To overcome this difficulty, we deposit them as thin layers by dispersing their nanoparticles in a gel containing a matrix that can maintain at least their bulk properties. After this size reduction at nanoscale and the annealing process following the deposition, changes and structural transformations would occur. We fabricate with success thin films by dispersing these nanoparticles in a gel. The materials show some agglomeration at the surface of the silicon substrate films (from SEM images) and non-identified hexagonal microcrystals, which could be at the origin of their excellent properties.

The present work relates to a process for silicon surface texturing for preparing large-area, silicon nanotextures on silicon substrates at ambient temperature by assisted chemical etching. A novel strategy comprises of two fundamental steps (metal-assisted chemical etching (MACE) and solution post-treatment) of using the silver catalyst to obtain specific nano- or micro-textures. The strategy is based on metal-induced (Ag) local oxidation and dissolution of a silicon substrate in three different concentrations of aqueous fluoride solution with the post-treatment solution. The etching technique is dependent on the etching time and concentration of aqueous fluoride solution. Therefore, detailed scanning electron microscopy observations reveal specifics shapes as inverted pyramids, cubic nano-microholes, spiroconical nano-microholes and rhombohedral-stared nanosheet bouquets (called Nanobukets), obtained for the first time on a (100) silicon surface by this new variant of the MACE method named Double Etching Method (DEM). Silicon nanostructures are used in many nanotechnology applications such as nano-microelectronics, optoelectronics or biomedical applications. UV-Visible spectrometry measurements carried out made it possible to obtain the lowest reflectance and highest absorbance values who are 3% and 97%, respectively for the rhomboedral-stared nanosheet bouquets on (100) crystalline silicon substrates in the UV-visible-NIR wavelength range from 300 to 1200 nm.

In this work we show the size-dependent ferromagnetic behavior of undoped and Mn-doped PZN-4.5PT single crystals, consequently their multiferroic one. Undoped single crystals were tamisized and three different sizes powders were investigated showing a size dependence in such ferroelectric materials while no magnetism is observed for the non-oriented and oriented bulk single crystals. The results show the existence of an optimized grain sizes range (45 mu m <= D <= 63 mu m) in which the magnetism is the highest (around 0.08 emu/g). It is found that the maximum value of the relative strain decreases from 0.25% for undoped crystals to 0.20% for Mn-doped ones. The remanent magnetization M-r and coercivity (H-c) were found equal, respectively, to 2 x 10(-4) emu/g and 63 Oe for undoped and, 7 x 10(-4) emu/g and 66 Oe for Mn-doped PZN-4.5PT, indicating that PZN-4.5PT particles possessed weak ferromagnetic behavior. Mn doping increases highly the spontaneous magnetization from 7.5 x 10(-3) emu/g to 1.0 x 10(-3) emu/g, respectively for undoped and Mn-doped nanoparticles. Copyright (C) EPLA, 2019

The integration of ferroelectric materials as thin films has attracted considerable attention these last years thanks to their outstanding performances that allow considering new features for the realization of photovoltaic devices. Our study focuses on investigating structural, dielectric and ferroelectric properties of undoped and Mn doped PZN-4.5PT nanoparticles thin films on Silicon substrate. We fabricate very stable PZN-4.5PT nanoparticles thin films deposited on nanostructured silicon substrate with giant relative dielectric permittivity of 2.76 × 104 and 17.7 × 104 for respectively the undoped and Mn doped thin films. These values are very large compared to those found in single crystals and might be explained by the influence of the gel in which nanoparticles were dispersed. The SEM images show the crystallization of new hexagonal phases on the film surface probably coming from interaction between Si and the gel. The hysteresis loops permitted to determine the spontaneous polarization (Ps), remnant polarization (Pr) and coercive field Ec which are equal to 11.73 μC/cm2, 10.20 μC/cm2 and 20 V/cm, respectively for the undoped nanoparticles thin film and 22.22 μC/cm2, 19.32 μC/cm2 and 20 V/cm respectively for the Mn doped one. These values are high and correspond to the best ones found in literature compared to typical ferroelectric thin films.

This work involves an investigation of nanostructures, microelectronic properties and domain engineering of nanoparticles thin layers of Pb(Zn1/ 3Nb2/3)O3-PbTiO3 (PZN-PT) ferroelectric single crystals deposited on nanostructured silicon substrate. In this study, devices made from PZN-4.5PT nanoparticles thin films successfully deposited on silicon substrate have been studied and discussed. SEM images show the formation of local black circles and hexagonal shapes probably due to the nucleation of a new Si-gel component or phase induced by annealing. Micro Xray Fluorescence mapping shows that the high values of Si and B atoms (≅7 and 4 normalized unit respectively) can be explained by the fact that the substrate is p-type silicon. The most interesting result of optical measurements is the very good absorption for all the thin films in UV, Visible and NIR regions with values from 70% to 90% in UV, from 75% to 93% in Visible and NIR. Tauc plots present particularities (rarely encountered behavior) with different segments or absorption changes showing the presence of multiple band gaps coming from the heterogeneity of the thin films (nanowires, gel and nanoparticles). Their values are 1.9 and 2.8 eV for DKRN-Gel, 2.1 and 3.1 eV for DKRN-UD and 2.1 and 3.2 eV for DKRN-D) corresponding respectively to the band gap of nanowires and that of the gel while the last ones correspond to the undoped and doped nanoparticles (3.1 and 3.2 eV respectively).