Articole din publicaţii internaţionale: Recent submissions

  • Fabrication of photonic crystal circuits based on GaN ultrathin membranes by maskless lithography 
    VOLCIUC, Olesea; BRANISTE, Tudor; SERGENTU, Vladimir; URSAKI, Veaceslav; TIGINYANU, Ion M.; GUTOWSKI, Jürgen (Society of Photo-Optical Instrumentation Engineers, SPIE, 2015)
    We report on maskless fabrication of photonic crystal (PhC) circuits based on ultrathin (d~15 nm) nanoperforated GaN membranes exhibiting a triangular lattice arrangement of holes with diameters of 150 nm. Ultrathin GaN ...
  • Gold Electroplating as a Tool for Assessing the Conductivity of InP Nanostructures Fabricated by Anodic Etching of Crystalline Substrates 
    MONAICO, E. V.; TIGINYANU, I. M.; URSAKI, V. V.; NIELSCH, K.; BALAN, D.; PRODANA, M.; ENACHESCU, M. (The Electrochemical Society, 2017)
    Electroplating is shown to represent a simple and effective tool for assessing the conductivity of InP nanostructures fabricated by electrochemical etching of InP wafers. A mixture of nanowalls, nanowires and nanobelts was ...
  • Sensing up to 40atm Using Pressure-Sensitive Aero-GaN 
    DRAGOMAN, Mircea; CIOBANU, Vladimir; SHREE, Sindu; DRAGOMAN, Daniela; BRANISTE, Tudor; RAEVSCHI, Simion; DINESCU, Adrian; SARUA, Andrei; MISHRA, Yogendra K.; PUGNO, Nicola; ADELUNG, Rainer; TIGINYANU, Ion (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2019)
    This work reports on the fabrication and characterization of a robust pressure sensor based on aero-GaN. The ultraporous aeromaterial consists of GaN interconnected hollow micro-tetrapods with the wall thickness of about ...
  • Electron field emission from narrow band gap semiconductors InAs 
    LITOVCHENKO, V.; EVTUKH, A.; SEMENENKO, M.; GRYGORIEV, A.; YILMAZOGLU, O.; HARTNAGEL, H. L.; SIRBU, L.; TIGINYANU, I. M.; URSAKI, V. V. (IOP Publishing, 2007)
    We propose to use InAs for the development of effective electron field emitters on the basis of a new technological approach for the preparation of highly textured surfaces which allows one to obtain peculiar fine rod-like ...
  • Surface charge lithography for GaN micro- and nanostructuring 
    TIGINYANU, Ion M.; POPA, Veaceslav; SARUA, Andrei; HEARD, Peter J.; VOLCIUC, Olesea; KUBALL, Martin (Society of Photo-Optical Instrumentation Engineers, SPIE, 2009)
    We demonstrate the possibility for controlled micro- and nanostructuring of GaN layers by low-dose focusedion-beam (FIB) treatment with subsequent photoelectrochemical (PEC) etching. The proposed novel maskless approach ...
  • Novel phosphors based on porous materials 
    TIGINYANU, I. M.; URSAKI, V. V.; SIRBU, L.; ENAKI, M.; MONAICO, E. (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2009)
    Technological conditions have been developed for the preparation of nanocomposite phosphors based on porous InP, GaP and GaAs semiconductor as well as Al2O3 and TiO2 dielectric templates doped with rare earth and transition ...
  • Ultrafast third-order optical nonlinearity in SnS2 layered compound for photonic applications 
    PETRIS, Adrian; GHEORGHE, Petronela S.; VLAD, Valentin I.; RUSU, Emil; URSAKI, Veaceslav V.; TIGINYANU, Ion M. (ELSEVIER, 2018)
    The ultrafast nonlinear optical response of SnS2 layered compound, excited by high-repetition-rate ultrashort (fs) pulses at 1550 nm wavelength, is investigated for the first time by optical third harmonic generation. In ...
  • Flexible pressure sensor based on graphene aerogel microstructures functionalized with CdS nanocrystalline thin film 
    PLESCO, Irina; DRAGOMAN, Mircea; STROBEL, Julian; GHIMPU, Lidia; SCHÜTT, Fabian; DINESCU, Adrian; URSAKI, Veaceslav; KIENLE, Lorenz; ADELUNG, Rainer; TIGINYANU, Ion (ELSEVIER, 2018)
    In this paper, we report on functionalization of graphene aerogel with a CdS thin film deposited by magnetron sputtering and on the development of flexible pressure sensors based on ultra-lightweight CdS-aerogel nanocomposite. ...
  • Electrical characterization and cathodoluminescence microanalysis of AlN/GaN heterostructures 
    HUBBARD, S. M.; PAVLIDIS, D.; VALIAEV, V.; STEVENS-KALCEFF, M. A.; TIGINYANU, I. M. (ELSEVIER, 2002)
    Low-pressure MOCVD is used to grow AlN/GaN MIS-type heterostructures with AlN thickness between 3 and 35 nm. The two-dimensional electron gas (2DEG) Hall mobility was found to decrease with AlN thickness. The measured room ...
  • Superlensing with plane plates consisting of dielectric cylinders in glass envelopes 
    FOCA, E.; SERGENTU, V. V.; DASCHNER, F.; TIGINYNAU, I. M.; URSAKI, V. V.; KNÖCHEL, R.; FÖLL, H. (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2009)
    The approach of designing negative-refractive-index materials on the basis of dielectric rods with a gradient of the dielectric constant is tested experimentally. A triangular-lattice plane-parallel slab assembled from ...
  • Filiform Nanostructure Technologies Based on Microwire Stretching 
    IOISHER, A. M.; BADINTER, E. Ya.; POSTOLACHE, V.; MONAICO, E. V.; URSAKI, V. V.; SERGENTU, V. V.; TIGINYANU, I. M. (American Scientific Publishers, 2012)
    A technological route allowing one to integrate huge amounts of electrically isolated metal, semiconductor, or semimetal nanowires in glass fibers with the diameter of up to a few hundreds of micrometers is presented, and ...
  • Cathodoluminescence characterization of suspended GaN nanomembranes 
    STEVENS-KALCEFF, M. A.; TIGINYANU, I. M.; POPA, V.; BRANISTE, T.; BRENNER, P. (AIP Publishing LLC, 2013)
    Continuous suspended ~15 nm thick gallium nitride (GaN) nano-membranes have been investigated using cathodoluminescence microanalysis. The GaN nanomembranes are fabricated by focused ion beam (FIB) pre-treatment of GaN ...
  • The impact of nanoperforation on persistent photoconductivity and optical quenching effects in suspended GaN nanomembranes 
    VOLCIUC, Olesea; BRANISTE, Tudor; TIGINYANU, Ion; STEVENS-KALCEFF, Marion A.; EBELING, Jakob; ASCHENBRENNER, Timo; HOMMEL, Detlef; URSAKI, Veaceslav; GUTOWSKI, Jürgen (AIP Publishing LLC, 2013)
    We report on fabrication of suspended ~15 nm thick GaN membranes nanoperforated in an ordered fashion using direct writing of negative charges by focused ion beam and subsequent photoelectrochemical etching of GaN epilayers. ...
  • Design of titania nanotube structures by focused laser beam direct writing 
    ENACHI, Mihai; STEVENS-KALCEFF, Marion A.; SARUA, Andrei; URSAKI, Veaceslav; TIGINYANU, Ion (AIP Publishing LLC, 2013)
    In this work, we report on electrochemical fabrication of titania films consisting of nanotubes (NTs) and their treatment by focused laser beam. The results of sample characterization by optical and scanning electron ...
  • Photonic Crystal Structures Based on GaN Ultrathin Membranes 
    VOLCIUC, Olesea; SERGENTU, Vladimir; TIGINYANU, Ion; SCHOWALTER, Marco; URSAKI, Veaceslav; ROSENAUER, Andreas; HOMMEL, Detlef; GUTOWSKI, Jürgen (American Scientific Publishers, 2014)
    We report on maskless fabrication of ultrathin (d ~ 15 nm) nanoperforated GaN membranes exhibiting a triangular lattice arrangement of holes with a diameter of 150 nm, and show that these membranes represent an intermediate ...
  • Atomically thin semiconducting layers and nanomembranes: a review 
    DRAGOMAN, Mircea; DRAGOMAN, Daniela; TIGINYANU, Ion (IOP Publishing, 2017)
    This article reviews the main physical properties of atomically thin semiconductors and the electronic devices based on them. We start with graphene, describing its physical properties and growth methods, followed by a ...
  • Focusing slabs made of negative index materials based on inhomogeneous dielectric rods 
    SERGENTU, V. V.; URSAKI, V. V.; TIGINYANU, I. M.; FOCA, E.; FÖLL, H.; BOYD, Robert W. (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2006)
    We show the advantages of using inhomogeneous dielectric rods to design photonic crystals that behave as materials with negative refractive index. We found that the analysis of light scattering properties of inhomogeneous ...
  • Cathodoluminescence microscopy and spectroscopy of GaN epilayers microstructured using surface charge lithography 
    DÍAZ-GUERRA, C.; PIQUERAS, J.; VOLCIUC, O.; POPA, V.; TIGINYANU, I. M. (American Institute of Physics, 2006)
    Cathodoluminescence (CL) microscopy and spectroscopy have been used to investigate the optical properties of GaN microstructures patterned by Ar+ ion irradiation and subsequent photoelectrochemical (PEC) etching. Monochromatic ...
  • Porous II-VI vs. porous III-V semiconductors 
    LANGA, S.; TIGINYANU, I. M.; MONAICO, E.; FÖLL, H. (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2011)
    In this work a morphological comparison of porous structures obtained by means of electrochemical etching in II-VI (ZnSe, CdSe) and III-V (InP, GaAs, GaP) semiconductors is presented. It is shown that in III-V semiconductors ...
  • Photoinduced modification of surface states in nanoporous InP 
    LLOYD-HUGHES, J.; MÜLLER, S.; SCALARI, G.; BISHOP, H.; CROSSLEY, A.; ENACHI, M.; SIRBU, L.; TIGINYANU, I. M. (American Institute of Physics, 2012)
    Porous honeycombs of n-type InP were investigated by terahertz time-domain and x-ray photoemission spectroscopies. After photoexcitation the dark conductivity was found to increase quasi-irreversibly, recovering only after ...

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