V. Kazlauskienė

XRD, XPS, SEM/EDX and broadband impedance spectroscopy study of pyrophosphate (LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7) ceramics

LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7 were synthesised by solid-state reaction and ceramics were sintered. The structure of compounds was studied in the temperature range 300–700 K by X-ray diffraction. Ceramics’ surfaces were investigated by scanning electron microscope. Binding energies of Fe 2p, P 2p and O 1s core levels at ceramics’ surfaces have been determined by X-ray photoelectron spectroscopy and different valence states of Fe and P were detected. Elemental compositions of the compounds were studied by energy dispersive X-ray spectrometer. Impedance spectroscopy was performed in the frequency range 10 Hz–3 GHz and in the temperature interval 400–700 K. The changes of the activation energy of ionic conductivity at 528 and 550 K for LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7, respectively, were found. The phenomena can be related to disordering in the unit cells of the compounds.

Preparation and characterization of Li2.9Sc1.9−y Y y Zr0.1(PO4)3 (where y = 0, 0.1) solid electrolyte ceramics

The solid electrolyte Li2.9Sc1.9− y Y y Zr0.1(PO4)3 (where y = 0, 0.1) compounds belong to monoclinic symmetry (space group P21/n) at room temperature. The Zr 3d, Sc 2p, P 2p, Y 3d, O 1s, and Li 1s core level X-ray photoelectron spectra (XPS) were fitted. The Li ions in ceramics without Y occupy two different positions and in the ceramics with Y they occupy one position in the lattice. The deconvolutions of the Zr 3d, P 2p, Sc 2p, and Y 3d core level XPS are associated with different valence states on the surfaces of the investigated ceramics. Anomalies of enthalpy, change of activation energy of ionic conductivity, anomalies of dielectric permittivity in the temperature range 420–520 K of investigated compounds were found. The phenomena are related to diffuse structure phase transition in the compounds. At temperatures 600 and 900 K, the compounds belong to orthorhombic symmetry (space group Pbcn).

Ablation of silicon by picosecond pulses of laser radiation

UV laser radiation with picosecond pulse duration was applied for ablation of silicon. Micro-drilling and cutting of silicon wafers were performed by 266-nm radiation. The effect of laser fluence on ablation rate and drilling depth was investigated.Laser affected layer of a bulk material near cutting wall was investigated. SEM, AES, XPS and SIMS techniques were applied for analysis of a cross-section of the cut. The Ar-ion beam etching was used to make the depth profile of the layer. Elemental composition of subsurface layer and its thickness were estimated.Investigation was inspired by the promise of application of short pulse lasers for formation of microstructures used in production of sensors and high power pulsed microwave detectors.UV laser radiation with picosecond pulse duration was applied for ablation of silicon. Micro-drilling and cutting of silicon wafers were performed by 266-nm radiation. The effect of laser fluence on ablation rate and drilling depth was investigated.Laser affected layer of a bulk material near cutting wall was investigated. SEM, AES, XPS and SIMS techniques were applied for analysis of a cross-section of the cut. The Ar-ion beam etching was used to make the depth profile of the layer. Elemental composition of subsurface layer and its thickness were estimated.Investigation was inspired by the promise of application of short pulse lasers for formation of microstructures used in production of sensors and high power pulsed microwave detectors.