Stage 1, year 2014
In this stage were designed, modeled, and realized materials as bulk glass, powders and coatings by sol-gel, MS and PLD methods.
The influence of pH, temperature, time on the sol- gel process was investigated, in aim of obtaining powders and desired thin films.
Were analyzed the properties of vitreous blocks materials, powders and thin nanostructured vitreous films, by using DTA, Raman, FTIR spectroscopy and UV-VIS, thermal analyzes and Vickers micro hardness.
Correlation structure - properties was done by using XRD, XRF, SEM + EDS, EDAX, and AFM.
The magneto- optical properties were investigated by using a modified Kerr device.
Were obtained vitreous matrixes for targets, comprising network formers, phosphorus and boron oxides, together with modifiers and stabilizers, such as Li2O, Al2O3 and ZnO.
Targets of boro-phosphate glass, containing 3 mole% additives were prepared by using p.a. reagents, by melting in electric furnace with superkanthal elements, at 1200-12500C for 2-4 hours, in alumina crucibles.
For improving the quality of glass the melt was mechanically homogenized by using an alumina stirrer.
The annealing was done in an electric furnace with kanthal elements at 480oC, for 4 hours.
The Raman spectra identified the structural symmetric and asymmetric units (POP) Q2 and Q1 at 328/350 and respectively 718/725 cm-1.
The delay about 950 cm-1 and 1180/1190 cm-1 are attributed to symmetric and asymmetric (PO2) in Q2 units and (PO3)2- as Q1 units.
The presence of BOB Q2 and Q1 units is evidenced by the maxima at 660 and respectively 950 cm-1. The maximum at 470 cm-1 is attributed to bending (BOB) units.
The UV- VIS transmittance is 90 % on whole domain for BPM2 sample. Maximum absorption peaks characteristics for Co2 + ions are evidenced in BPM3 sample.
Sol- gel experiments
They were made two set of samples.
In first stage were used as starting material H3BO3 which was dissolved in 2.82 ml H2O.
Then was introduced H3PO4, 4.23 ml, and C2H5OH, (50%) 13.74ml. To modify the pH was added NH4OH, to increase from 1.5 to 3.5.
Samples were thermal treated at 40 0C for 1h and at 50 0C for 1h.
In the second stage were prepared 5 samples starting from B2O3 and TEP, C2H5OH and 2.83 ml H2O.
To homogenize were micro wave treated at 60 0C for 10 min. The pH variation was from 3 to 6.
Then were made thermal treatments at 120 0C for 1h, and at 1500C for 2h.
Were obtained dried gels for 3 samples at pH 3, 4 and 5.
Thin films were obtained by PLD and MSD deposition.
Experimental data for PLD were: laser KrF, Fluence 2.5 J/cm2; Ts=400-800 oC; Pressure 10-4 mbar O2; 12500 – 25000 pulses; film growth 200 -1000 nm.
The working conditions are presented in the table below.
|Substrate||Quartz glass||Quartz glass||Quartz glass||Quartz glass|
glass BPM2 code
glass BPM2 code
glass BPM2 code
glass BPM2 code
|Fluence||2.7 J/cm2||2.7 J/cm2||2.7 J/cm2||2.7 J/cm2|
|Target-substrate distance||8 cm||8 cm||8 cm||8 cm|
|Pressure||10-4 mbar O2||10-4 mbar O2||10-4 mbar O2||10-4 mbar O2|
XRD showed that the obtained films were amorphous.
The AFM investigations pointed out that the substrate temperature influence the thickness of thin films from BPM2 target, obtained by PLD.
Using AFM were measured the thickness of the thin films obtained by PLD: the films deposited at 400 °C, fad double thickness comparatively to that obtained at 600 °C.
Roughness is influenced by the numbers of pulses. Roughness increases from 60 nm to 150 nm at 400 °C, respectively from 20 nm to 50 nm at 600 °C when the number of pulses grows from 12500 to 25000.
AFM investigation showed that the temperature of substrate influenced the thickness of thin films obtained by PLD from BPM2 target. Using AFM was measured the thickness of the film deposited by PLD at 400 °C, being about double compared with the one obtained at 600 °C.
Obtaining of films by MS
Magnetron sputtering deposition (MS) is a PVD process of deposition from vapors, technologic process used in many industrial techniques for thin layers deposition on different substrates. This technique realizes physically very thin layers (nanometers) or thick layers (microns) having a very good adherence to the substrate, stoichiometry and uniformity, from mechanical and optical point of view.
The deposition of the layers (metal, semiconductor or dielectric) on substrate is made in vacuum (10-4torr – 10-2torr) by bombardment the target (material to be deposited) with energetic ions, in most cases being Ar ions. The gaze in these depositions having good efficiency / yield of pulverization is Argon. This was used by us. After the interaction with the Argon ions the atoms of the material for deposition are released and accelerated in electric and magnetic simulated field (RF) toward the substrate. The deposition process in the formed plasma between the target and substrate is linear and uniform on all substrate surface.
The working condition were the following: Ar pressure, 1x10 -4 torr (30 cm3), active power 100 W, intensity of current 0.2 A, deposition speed 0.6-0.8 Ǻ/s, thickness layer 0.5 micron.
Magneto optical properties
Faraday magnetometer with longitudinal sample cell was used for measuring magnetic properties at the wavelength of 630 nm. Rotation obtained with this device was 0.4 degrees, close to ellipsometry measurements results.
Abstract stage 2, 2015, for the MAGPHOGLAS project, M-ERA.NET 7-081/2013
In this stage were obtained the following:
- Experiments to obtain coatings from boro -phosphate materials by sol-gel method and targets for MS and PLD by melting –quenching and annealing method;
- From boro - phosphate materials, the basic receipt and doped with rare earth ions and post transitional elements were obtained thin films by spin coating method and targets for MS and PLD depositions;
- The block materials and thin films were characterized by UV-Vis spectroscopy, FTIR, Raman, AFM, SEM, XRD, luminescence analyses and mechanical properties;
- The magneto-optical properties were measured by a modified Kerr device.
- Was realized a Faraday rotator prototype;
- Dissemination of the obtained results.
Obtaining of vitreous targets
Were obtained targets for MS and PLD based on vitreous matrixes containing network formers boron and phosphorus oxides, together with modifiers and stabilizers such as Li2O, Al2O3 and ZnO.
Targets from boro-phosphate glass, containing 6 mol % dopants, were prepared from pure reagents, p.a. by melting in electric furnace with superkantal elements, at 1200-12500C, time 2-4 h, in alumina crucibles. In order to increase the glass quality the melt was homogenized by an alumina stirrer.
The annealing was done in an electric furnace with kanthal elements, at 480oC, for 4 h.
Optimized sol-gel experiments
To optimize the obtaining of sol-gel coatings from boro-phosphate systems doped and undoped was first optimized the method of powder and layers obtaining by sol-gel from the base recipe, containing only phosphorus and boron oxides.
Were used as starting materials B2O3, that was dissolved in 2.82 ml H2O, 4.23 ml H3PO4 and 13.74 ml C2H5OH. In order to fix the pH was added 1N solution of HCl or solution 25% NH4OH, obtaining pH from 1.5 to 3, respectively 7-8.
Samples were thermal treated at 40 0C for 1 h and than at 50 0C, for 1h.
Were made experiments to deposit coatings from the obtained sols, but without high quality results.
Were prepared four samples starting from B2O3 and TEP, C2H5OH and 2.83 ml H2O, together with the dopants DyCl3.6H2O and TbCl3.6H2O.The pH variations was from 1.5 to 3.
For homogenization the samples were introduced in an ultrasound bath, at 40 0C for 10 min. From samples 1 and 2 were deposited by spin –coating method, on boro- silicate and silica glass substrates, at speeds between 1000 and 1500 rot/min, time 30 s, 10 layers each, with thermal treatments between depositions at cca 100oC for 30 s, and in the end at 100 oC for 1 h.
The quality of the depositions was investigated by AFM.
Thin films obtained by PLD
Were deposited films by PLD method from BPM6 targets on boro-silicate glass, quartz glass and silica substrates.
The process parameters were:
Laser KrF, wave length 248 nm; Fluency: 1.5 J/cm2 ; Frequency 40 Hz ; Pressure room: 0.012-0.3 Pa; Pulse number: 13000 and 25000 ; Substrate temperature: 50 – 600oC.
The obtained samples were characterized by AFM, the roughness being over 100 nm.
It were made depositions at 193 nm wave length, frequency 20 Hz, 72000 pulses and fluency 1.0 J/cm2. Substrate temperature was 300 oC and the pressure 5x10-2 bar.
The first obtained sample is under characterization by profilometry, to determine the film growth and by AFM to establish the deposition roughness.
Model and design of meta-materials and boro-phosphate nano structurated vitreous materials with negative refractive index
The experiments were made on an installation RF magnetron sputtering assisted by an ion gun, technological device type VARIAN ER 3119.
In the reaction camber were placed the substrates BPM2 and boro-silicate glass at 100 mm distance against the magnetron cathode.
A 99.99% Ag target was placed at the magnetron cathode M1. The vide cycle by “CRYO pumps VARIAN VS eight” took 4 h, in order to obtain 4.5 x 10-6 torr.
The deposition of Ag layer was done in controlled atmosphere Argon 99.99% at flow 25 s.c.cm and a partial pressure 4.5 x 10-4 torr.
The evaporation speed was constant 0.5 Ǻ/s – 0.9 Ǻ/s. The film thickness was 3 nm + 0.5 nm.
The realized experiments were demonstrated by fine controlled morphology of Ag surfaces (processed by ion beam with energy under 1500 eV) increase of details at 30 nm with an illumination between 400 nm- 500 nm. The spectra recorded at QE 1400 confirmed the experimental result.
Determination of properties for the obtained materials
Partner New University of Lisbon, Faculty of Science and Technology-I3N/CENIMAT made the characterization of the obtained films by sol- gel, PLD, and MS methods, by UV-Vis, SEM-EDS, DRX and of powders materials by SEM-EDS, XRD. The same partner determined the luminescence properties of sample BPM6.
Was used a Faraday longitudinal magnetometer with the measure cell with transparent block at 630 nm wave length. For sample BMPG 2d_1 and BMPG 2d_2, the magnetic measurements put into evidence a paramagnetic behavior till the lowest temperature (5 K) and a magnetic susceptibility 4 times bigger in the second sample, the value was closed to hath the magnetite value.
Were realized mechanical properties measurements, nano indentation, micro hardness, Young module, by partners from Applied Physics Institute of Academy of Sciences of Republica Moldova from Chisinau.
Realization of Faraday rotator prototype / ultra fast comutator opto -magnetic based on BPG (boro- phosphate glass);
Based on an original conception, design and development by partner SITEX it was realized the design documentation and realization, under patent, for two types of opto-magnetic comutators based on BPM2/6 (boro- phosphate glass).
For the design and fabrication of protopype the base was the functionality of a classic opto- magnetic comutator.
Dissemination by publication of papers and presentations of the project results at International Conferences
The dissemination of the project results was made by publishing 2 articles in ISI journals, 2 articles accepted for publication in ISI journals, and by presentation of 8 scientific papers at International Conferences.
During 18-22.06.2015 at Lisbon took place the project partners meeting. Partner SITEX made a patent deposition.