Now showing items 1-20 of 46

    • 2D material liquid crystals for optoelectronics and photonics 

      Hogan B.T.; Kovalska E.; Craciun M.F.; Baldycheva A. (Royal Society of Chemistry, 2017)
      The merging of the materials science paradigms of liquid crystals and 2D materials promises superb new opportunities for the advancement of the fields of optoelectronics and photonics. In this review, we summarise the ...
    • AlGaN quadruple-band photodetectors 

      Gökkavas, M.; Butun, S.; Caban P.; Strupinski W.; Ozbay, E. (2009)
      Quadruple back-illuminated ultraviolet metal-semiconductor-metal photodetectors with four different spectral responsivity bands were demonstrated. The average of the full-width at half-maximum (FWHM) of the quantum efficiency ...
    • AlxGa1-xN-based avalanche photodiodes with high reproducible avalanche gain 

      Tut, T.; Gokkavas, M.; Ozbay, E. (2008)
      We report high performance solar-blind photodetectors with reproducible avalanche gain as high as 1570 under ultraviolet illumination. The solar-blind photodetectors have a sharp cut-off around 276 nm. The dark currents ...
    • Blue organic light-emitting diodes based on pyrazoline phenyl derivative 

      Stakhira, P.; Khomyak, S.; Cherpak, V.; Volyniuk, D.; Simokaitiene, J.; Tomkeviciene, A.; Kukhta, N.A.; Grazulevicius, J.V.; Kukhta, A.V.; Sun, X.W.; Demir, H. V.; Hotra, Z.; Voznyak, L. (Elsevier, 2012-01-21)
      The results of an experimental study of the electroluminescent device made of ITO/CuI/2,6-di-tert.-butyl-4-(2,5-diphenyl-3,4-dihydro-2H-pyrazol-3-yl)- phenol (HPhP)/3,6-Di(9-carbazolyl)-9-(2-ethylhexyl) carbazole (TCz1)/Ca:Al ...
    • CDs have fingerprints too 

      Hammouri G.; Dana, A.; Sunar, B. (2009)
      We introduce a new technique for extracting unique fingerprints from identical CDs. The proposed technique takes advantage of manufacturing variability found in the length of the CD lands and pits. Although the variability ...
    • Colloidal nanoplatelet/conducting polymer hybrids: excitonic and material properties 

      Guzelturk, B.; Menk, F.; Philipps, K.; Kelestemur Y.; Olutas M.; Zentel, R.; Demir, H. V. (American Chemical Society, 2016)
      Here we present the first account of conductive polymer/colloidal nanoplatelet hybrids. For this, we developed DEH-PPV-based polymers with two different anchor groups (sulfide and amine) acting as surfactants for CdSe ...
    • Colloidal quantum dot light-emitting diodes employing phosphorescent small organic molecules as efficient exciton harvesters 

      Mutlugun, E.; Guzelturk, B.; Abiyasa, A. P.; Gao, Y.; Sun X. W.; Demir, H. V. (American Chemical Society, 2014)
      Nonradiative energy transfer (NRET) is an alternative excitation mechanism in colloidal quantum dot (QD) based electroluminescent devices (QLEDs). Here, we develop hybrid highly spectrally pure QLEDs that facilitate energy ...
    • Compressive sensing imaging with a graphene modulator at THz frequency in transmission mode 

      Ozkan V.A.; Takan T.; Kakenov N.; Kocabas C.; Altan H. (IEEE Computer Society, 2016)
      In this study we demonstrate compressive sensing imaging with a unique graphene based optoelectronic device which allows us to modulate the THz field through an array of columns or rows distributed throughout its face. © ...
    • Controlled growth and characterization of epitaxially-laterally-overgrown InGaN/GaN quantum heterostructures 

      Sari, E.; Akyuz O.; Choi, E.-G.; Lee I.-H.; Baek J.H.; Demir, H. V. (2010)
      Crystal material quality is fundamentally important for optoelectronic devices including laser diodes and light emitting diodes. To this end epitaxial lateral overgrowth (ELO) has proven to be a powerful technique for ...
    • Dark current reduction in ultraviolet metal-semiconductor-metal photodetectors based on wide band-gap semiconductors 

      Bütün, S.; Gökkavas, M.; Yu H.; Strupinski V.; Özbay, E. (2009)
      Photodetectors on semi-insulating GaN templates were demonstrated. They exhibit lower dark current compared to photodetectors fabricated on regular GaN templates. Similar behavior observed in photodetectors fabricated on ...
    • Design of dynamically adjustable anamorphic fractional Fourier transformer 

      Erden, M. F.; Ozaktas, H. M.; Sahin, A.; Mendlovic, D. (Elsevier BV * North-Holland, 1997-03-01)
      We form optical systems by using only free space portions and cylindrical lenses, and consider these systems as anamorphic fractional Fourier transformers. We dynamically adjust the transform order, scale factor and field ...
    • Electrically-reconfigurable integrated photonic switches 

      Fidaner O.; Demir, H. V.; Sabnis V.A.; Harris Jr. J.S.; Miller, D.A.B.; Zheng J.-F. (2004)
      We report remotely electrically reconfigurable photonic switches that intimately integrate waveguide electroabsorption modulators with surface-normal photodiodes, avoiding conventional electronics. These switches exhibit ...
    • Enhanced tunability of V-shaped plasmonic structures using ionic liquid gating and graphene 

      Ozdemir, O.; Aygar, A. M.; Balci, O.; Kocabas, C.; Caglayan, H.; Ozbay, E. (Elsevier Ltd, 2016)
      Graphene is a strong candidate for active optoelectronic devices because of its electrostatically tunable optical response. Current substrate back-gating methods are unable to sustain high fields through graphene unless a ...
    • Exact calculation of blocking probabilities for bufferless optical burst switched links with partial wavelength conversion 

      Akar, N.; Karasan, E. (2004)
      In this paper, we study the blocking probabilities in a wavelength division multiplexing-based asynchronous bufferless optical burst switch equipped with a bank of tuneable wavelength converters that is shared per output ...
    • Experimental investigation of layer-by-layer metallic photonic crystals 

      Temelkuran, B.; Altug, H.; Ozbay, E. (Institution of Electrical Engineers, 1998-12)
      The authors have investigated the transmission properties and defect characteristics of layer-by-layer metallic photonic crystals. They have demonstrated experimentally that the metallicity gap of these crystals extends ...
    • Generation of ultra-small InN nanocrystals by pulsed laser ablation of suspension in organic solution 

      Kurşungöz, C.; U. Şimşek, E.; Tuzaklı, R.; Ortaç, B. (Springer Verlag, 2017-03)
      Nanostructures of InN have been extensively investigated since nano-size provides a number of advantages allowing applications in nanoscale electronic and optoelectronic devices. It is quite important to obtain pure InN ...
    • Graphene-based optical modulators 

      Balci S.; Kocabas, C. (World Scientific Publishing Co. Pte. Ltd., 2017)
      In this chapter, we summarize the recent progress on graphene based optical modulators. Ability to control density of high mobility electrons on large area graphene surface enables realization of new type of electrooptical ...
    • Graphene-enabled optoelectronics on paper 

      Polat, E. O.; Uzlu, H. B.; Balci, O.; Kakenov, N.; Kovalska, E.; Kocabas, C. (American Chemical Society, 2016-06)
      The realization of optoelectronic devices on paper has been an outstanding challenge due to the large surface roughness and incompatible nature of paper with optical materials. Here, we demonstrate a new class of optoelectronic ...
    • Growth of ∼3-nm ZnO nano-islands using Atomic layer deposition 

      El-Atab, N.; Chowdhury, F. I.; Ulusoy, T. G.; Ghobadi, A.; Nazirzadeh, A.; Okyay, A. K.; Nayfeh, A. (Institute of Electrical and Electronics Engineers Inc., 2016)
      In this work, the deposition of 3-nm dispersed Zinc-Oxide (ZnO) nanislands by thermal Atomic Layer Deposition (ALD) is demonstrated. The physical and electronic properties of the islands are studied using Atomic Force ...
    • High efficiency monolithic photodetectors for integrated optoelectronics in the near infrared 

      Okyay, A., K.; Onbasli, M.C.; Ercan, B.; Yu H.-Y.; Ren, S.; Miller, D.A.B.; Saraswat, K.C.; Nayfeh, A.M. (2009)
      Monolithic Germanium photodetectors integrated on Si with external efficiency up to 68% at 1550nm and low dark current density 3.2mA/cm2 are demonstrated. The absorption edge red shifted by 47nm corresponding to bandgap ...