0000000000636724

AUTHOR

Kęstutis Jarašiūnas

showing 3 related works from this author

Influence of boron on donor–acceptor pair recombination in type IIa HPHT diamonds

2013

Abstract We report on the investigation of donor–acceptor pair (DAP) and free carrier recombination in HPHT IIa type diamonds and determination of boron concentration by differential transmittivity (DT) technique. Photoluminescence and photoluminescence excitation spectra were measured in 8–300 K temperature range and provided a broad (~ 0.67 eV) Gaussian DAP band which peaked at 2.2 eV at low temperatures, while above 200 K it sharply shifted to 2.5 eV and became more intense. Thermoluminescence measurements also demonstrated a similar tendency. This peculiarity was explained by DAP recombination between the nitrogen and the boron, the latter being in the ground and the excited states at l…

PhotoluminescenceMechanical EngineeringAnalytical chemistrychemistry.chemical_elementGeneral ChemistryActivation energyAtmospheric temperature rangeThermoluminescenceElectronic Optical and Magnetic MaterialschemistryExcited stateIonizationMaterials ChemistryPhotoluminescence excitationElectrical and Electronic EngineeringBoronDiamond and Related Materials
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Photo-electrical and transport properties of hydrothermal ZnO

2016

We performed the studies of optical, photoelectric, and transport properties of a hydrothermal bulk n-type ZnO crystal by using the contactless optical techniques: photoluminescence, light-induced transient grating, and differential reflectivity. Optical studies revealed bound exciton and defect-related transitions between the donor states (at ∼60 meV and ∼240 meV below the conduction band) and the deep acceptor states (at 0.52 eV above the valence band). The acceptor state was ascribed to VZn, and its thermal activation energy of 0.43 eV was determined. A low value of carrier diffusion coefficient (∼0.1 cm2/s) at low excitations and temperatures up to 800 K was attributed to impact the rec…

010302 applied physicsElectron mobilityPhotoluminescenceChemistryBand gapExcitonWide-bandgap semiconductorGeneral Physics and Astronomy02 engineering and technologyCarrier lifetime021001 nanoscience & nanotechnology01 natural sciencesAcceptorMolecular physicsCrystalCondensed Matter::Materials Science0103 physical sciencesAtomic physics0210 nano-technologyJournal of Applied Physics
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Carrier dynamics in epilayers and nanocolumns of ternary AlGaN with a tunable bandgap

2012

We apply several optical time-resolved techniques to investigate the dynamics of excess carriers in AlxGa1−xN nanocolumns grown on (111) silicon substrates and in thick AlxGa1−xN epitaxial layers deposited on sapphire. We demonstrate that carrier lifetime drops in nanocolumns by several times if compared to epilayers with similar Al content; in addition, recombination rate displays a strong nonlinearity on excitation. On the other hand, carrier localization effects observed in the epilayers completely disappear in nanocolumns.

Materials scienceSiliconbusiness.industryBand gapchemistry.chemical_elementCarrier lifetimeEpitaxychemistrySapphireOptoelectronicsTernary operationCarrier dynamicsbusinessExcitationIOP Conference Series: Materials Science and Engineering
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