Selected publications in 2015

Longitudinal spin-relaxation in nitrogen-vacancy centers in electron irradiated diamond

A. Jarmola, A. Berzins, J. Smits, K. Smits, J. Prikulis, F. Gahbauer, R. Ferber, D. Erts, M. Auzinsh, and D. Budker We present systematic measurements of longitudinal relaxation rates (1=T1) of spin polarization in the ground state of the nitrogen-vacancy (NV–) color center in synthetic diamond as a function of NV– concentration and magnetic field […]

Posted in 2015, Applied Physics Letters, Publications, Smits | Tagged , , , | Leave a comment

Luminescence of polymorphous SiO2

A.N. Trukhin, K. Smits, J. Jansons, A. Kuzmin The luminescence of self-trapped exciton (STE) was found and systematically studied in tetrahedron structured silica crystals (a-quartz, coesite, cristobalite) and glass. In octahedron structured stishovite only host material defect luminescence was observed. It strongly resembles luminescence of oxygen deficient silica glass and g or neutron irradiated a-quartz. […]

Posted in 2015, Publications, Radiation Measurements, Smits | Tagged , , , | Leave a comment

Multicolor upconversion luminescence of GdVO4:Ln3þ/Yb3þ (Ln3þ ¼ Ho3þ, Er3þ, Tm3þ, Ho3þ/Er3þ/Tm3þ) nanorods

Tamara V. Gavrilovic , Dragana J. Jovanovic,  Krisjanis Smits, Miroslav D. Dramicanin  Lanthanide-doped GdVO4 nanorods that exhibit upconversion emission under 982 nm excitation have been prepared by a facile room-temperature chemical co-precipitation method followed by a subsequent annealing at temperatures of 600 C, 800 C and 1000 C. Multicolor upconversion emission, including white, was achieved […]

Posted in 2015, Dyes and Pigments, Publications, Smits | Tagged , , , | Leave a comment

Gas sensitive luminescence of ZnO coatings obtained by plazmaelectrolytic oxidation

L. Grigorjeva, D. Millers, K. Smits, A. Zolotarjovs The ZnO coatings on Zn substrate were obtained using plasma electrolytic oxidation method. The XRDand SEM methods were used for structural and morphological characterization of obtained coatings. Theluminescence of ZnO coatings were studied and compared with luminescence characteristics of ZnO sin-gle crystal. It is shown that luminescence […]

Posted in 2015, Grigorjeva, Millers, Publications, Sensors and Actuators, Smits, Zolotarjovs | Tagged , , , , , | Leave a comment

Raman, electron microscopy and electrical transport studies of x-ray amorphous Zn-Ir-O thin lms deposited by reactive DC magnetron sputtering

M. Zubkins, R. Kalendarev, J. Gabrusenoks, K. Smits, K. Kundzins, K. Vilnis, A. Azens, J. Purans Abstract. Zn-Ir-O thin lms on glass and Ti substrates were deposited by reactive DC magnetron sputtering at room temperature. Structural and electrical properties were investigated as a function of iridium concentration in the lms. Raman spectrum of Zn-Ir- O […]

Posted in 2015, IOP Conference Series: Materials Science and Engineering, Publications, Smits | Tagged , , , , , | Leave a comment

Luminescence of Er/Yb and Tm/Yb doped FAp nanoparticles and ceramics

L. Grigorjeva, K. Smits, D.Millers, Dz.Jankoviča Abstract. The nanoparticles of hydroxiapatite and fluorapatite doped with Er/Yb and Tm/Yb were synthesized and characterized by FTIR, XRD, SEM and TEM methods. The results of up-conversion luminescence studies were presented for the samples as prepared, annealed at 500°C and at 900-1000 °C. At annealing above 800°C the ceramic […]

Posted in 2015, Grigorjeva, IOP Conference Series: Materials Science and Engineering, Millers, Publications, Smits | Tagged , , , , , , | Leave a comment

UV and yellow luminescence in phosphorus doped crystalline and glassy silicon dioxide

A.N.Trukhin , K.Smits , J.Jansons , D.Berzins , G.Chikvaidze , D.L.Griscom  Luminescence of phosphorus doped crystalline α-quartz and phosphosilicate glass with content 3P2O5  7SiO2 was studied.Water and OH groups are found by IR spectra in these materials.The spectrum of lumines cence contains many bands in the range 1.5–5.5 eV. The luminescence bands in UV range […]

Posted in 2015, Journal of Luminescence, Publications, Smits | Tagged , , , , , | Leave a comment

Luminescence of Eu ion in alumina prepared by plasma electrolyticoxidation

Krisjanis Smitsa, Donats Millers, Aleksejs Zolotarjovs,Reinis Drunka, Martins Vanks Eu ion luminescence in aluminium oxide nanocrystals and layers prepared by plasma electrolytic oxida-tion (PEO) are investigated in this study. The Eu ion in PEO coatings has intense luminescence allowingsuch material to be used for preparation of various phosphor materials. In this study, Eu ion doped […]

Posted in 2015, Applied Surface Science, Millers, Publications, Smits, Zolotarjovs | Tagged , , , , , | Leave a comment