Recent Submissions

  • Phase transitions and renormalization-group theory 

    Berker, A. Nihat (1989-07)
    The study of critical phenomena targets the qualitatively new phenomena that occur through the interactions of very large numbers of degrees of freedom. Such situations are typically realized near the onset of the transition ...
  • Exceptional adaptable MWIR thermal emission for ordinary objects covered with thin VO2 film 

    Durna, Yılmaz; Kocer, Hasan; Aydın, Koray; Cakir, Mehmet Cihan; Soydan, Mahmut Can; Odabasi, Oguz; Işık, Halil; Ozbay, Ekmel (Elsevier Ltd, 2021-01-25)
    Monotonous thermal radiation emitted from an ordinary object can be brought into a dynamic and versatile form that can be shaped according to the application area with the ingenious design of the surface coatings. Building ...
  • Current transport properties of (Au/Ni)/HfAlO3/n-Si metal–insulator–semiconductor junction 

    Arslan, Engin; Badali, Yosef; Aalizadeh, Majid; Altındal, Semsettin; Ozbay, Ekmel (Elsevier Ltd, 2020-09-11)
    In this study, HfAlO3 ternary alloy thin film was grown on n-type silicon using the atomic layer deposition method. The current transport mechanisms in the (Au/Ni)/HfAlO3/n-Si junction were examined over a wide temperature ...
  • The pulse shape effect on signal-to-noise ratio for φ-OTDR systems 

    Uyar, Faruk; Nehir, Anıl; Kartaloğlu, Tolga; Özbay, Ekmel; Özdur, İ. (Optica Publishing Group, 2021)
    We experimentally investigate the effect of the probe pulse shape on the performance of φ-OTDR based distributed vibration sensors by comparing the SNR values for rectangular, Gaussian and triangular pulses.
  • Spatial resolution analysis of dual-pulse ϕ-OTDR systems 

    Yıldız, Muhammed Kaan; Uyar, Faruk; Kartaloğlu, Tolga; Özbay, Ekmel; Özdur, İ. (Optica Publishing Group, 2021)
    This work analyzes the spatial resolution of the dual-pulse -OTDR systems by changing the dual-pulse parameters and demonstrates that the spatial resolution corresponds to half of the fiber region occupied by the dual-pulse train.
  • State of the art and prospects for Halide Perovskite nanocrystals 

    Dey, A.; Ye, J.; De, A.; Debroye, E.; Ha, S. K.; Bladt, E.; Kshirsagar, A. S.; Wang, Z.; Yin, J.; Wang, Y.; Quan, L. N.; Yan, F.; Gao, M.; Li, X.; Shamsi, J.; Debnath, T.; Cao, M.; Scheel, M. A.; Kumar, S.; Steele, J. A.; Gerhard, M.; Chouhan, L.; Xu, K.; Wu, X-g; Li, Y.; Zhang, Y.; Han, C.; Dutta, A.; Vincon, I.; Rogach, A. L.; Nag, A.; Samanta, A.; Korgel, B. A.; Shih, C.-J.; Gamelin, D. R.; Son, D. H.; Zeng, H.; Zhong, H.; Sun, H.; Demir, Hilmi Volkan; Scheblykin, I. G.; Mora-Seró, I.; Stolarczyk, J. K.; Zhang, J. Z.; Feldmann, J.; Hofkens, J.; Luther, J. M.; Pérez-Prieto, J.; Li, L.; Manna, L.; Bodnarchuk, M. I.; Kovalenko, M. V.; Roeffaers, M. B. J.; Pradhan, N.; Mohammed, O. F.; Bakr, O. M.; Yang, P.; Müller-Buschbaum, P.; Kamat, P. V.; Bao, Q.; Zhang, Q.; Krahne, R.; Galian, R. E.; Stranks, S. D.; Bals, S.; Biju, V.; Tisdale, W. A.; Yan, Y.; Hoye, R. L. Z.; Polavarapu, L. (American Chemical Society, 2021-06-17)
    Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics ...
  • Single-mode lasing from a single 7 nm thick monolayer of colloidal quantum wells in a monolithic microcavity 

    Foroutan-Barenji, Sina; Erdem, Onur; Delikanlı, Savaş; Yağcı, Hüseyin Bilge; Gheshlaghi, Negar; Altıntaş, Yemliha; Demir, Hilmi Volkan (Wiley-VCH Verlag, 2021-03-03)
    In this work, monolithically-fabricated vertical cavity surface emitting lasers (VCSELs) of densely-packed, orientation-controlled, atomically flat colloidal quantum wells (CQWs) using a self-assembly method is reported ...
  • Correction to: Active tuning from narrowband to broadband absorbers using a sub-wavelength VO2 embedded layer 

    Osgouei, Ataollah Kalantari; Hajian, Hodjat; Khalichi, Bahram; Serebryannikov, Andriy E.; Ghobadi, Amir; Özbay, Ekmel (Springer, 2021-02-04)
    Metamaterial perfect absorbers (MPAs) with dynamic thermal tuning features are able to control the absorption performance of the resonances, providing diverse applications spanning from optical switches and filters to ...
  • Near-field energy transfer into silicon inversely proportional to distance using quasi-2D colloidal quantum well donors 

    Humayun, Muhammad Hamza; Hernandez-Martinez, Pedro Ludwig; Gheshlaghi, Negar; Erdem, Onur; Altıntaş, Yemliha; Shabani, Farzan; Demir, Hilmi Volkan (Wiley-VCH Verlag GmbH & Co. KGaA, 2021-09-12)
    Silicon is the most prevalent material system for light-harvesting applications; however, its inherent indirect bandgap and consequent weak absorption limits its potential in optoelectronics. This paper proposes to address ...
  • Optical microfluidic waveguides and solution lasers of colloidal semiconductor quantum wells 

    Maskoun, Joudi; Gheshlaghi, Negar; Işık, Furkan; Savaş, Delikanlı; Onur, Erdem; Emine Yegan, Erdem; Hilmi Volkan, Demir (Wiley-VCH Verlag GmbH & Co. KGaA, 2021-01-25)
    The realization of high-quality lasers in microfluidic devices is crucial for numerous applications, including biological and chemical sensors and flow cytometry, and the development of advanced lab-on-chip (LOC) devices. ...
  • Spin-gapped magnets with weak anisotropies I: Constraints on the phase of the condensate wave function 

    Rakhimov, Abdulla; Khudoyberdiev, A.; Rani, Luxmi; Tanatar, Bilal (Elsevier, 2020-11-27)
    We study the thermodynamic properties of dimerized spin-gapped quantum magnets with and without exchange anisotropy (EA) and Dzyaloshinsky and Moriya (DM) anisotropies within the mean-field approximation (MFA). For this ...
  • An investigation of fidelity regions in the dual-pulse 𝝓-OTDR systems 

    Yıldız, Muhammed Kaan; Uyar, Faruk; Kartaloǧlu, Tolga; Ozdur, İ. T.; Özbay, Ekmel (The Optical Society, 2021)
    The dual-pulse interrogation enables the phase extraction from the intensity of the backreflection signal in 𝜙-OTDR systems. We investigate the high and low fidelity regions in the back-reflected signal by analyzing the ...
  • A simple parity-time-symmetric optoelectronic oscillator based on all-fiber coupling 

    Özgün, Ege; Uyar, Faruk; Kartaloǧlu, Tolga; Özbay, Ekmel; Ozdur, İ. T. (The Optical Society, 2021)
    We experimentally demonstrate a simple parity-time-symmetric optoelectronic oscillator based on all-fiber coupling with single-mode microwave oscillation at 9.5 GHz possessing a phase noise value of −116.2 dBc/Hz at 10 kHz offset.
  • Analysis of the most precise light curves of HAT-P-36 detrended from spot signals 

    Yalçınkaya, S.; Baştürk, Ö.; El Helweh, Fadel; Esmer, E. M.; Yörükoğlu, O.; Yılmaz, M.; Şenavcı, H.V.; Kılıçoğlu, T.; Selam, S. O. (Fundacja Astronomii Polskiej im. Mikolaja Kopernika,Copernicus Foundation for Polish Astronomy, 2021-11-22)
    We study the most precise light curves of the planet-host HAT-P-36 that we obtained from the ground primarily with a brand-new 80 cm telescope very recently installed at Ankara University Kreiken Observatory of Turkey and ...
  • Substrate effects on electrical parameters of Dirac fermions in graphene 

    Tiras, E.; Ardali, S.; Firat, H. A.; Arslan, E.; Özbay, Ekmel (Elsevier, 2021-05-19)
    The substrate effects on the electronic transport properties of single-layer graphene on TiO2/Si substrate have been studied. The Hall mobility, sheet carrier density, and transport lifetime were obtained from the ...
  • Low-threshold lasing from copper-doped CdSe colloidal quantum wells 

    Yu, J.; Sharma, M.; Li, M.; Delikanlı, Savaş; Sharma, A.; Taimoor, M.; Altintas, Y.; McBride, J. R.; Kusserow, T.; Sum, T.; Demir, Hilmi Volkan (Wiley, 2021-05-04)
    Transition metal doped colloidal nanomaterials (TMDCNMs) have recently attracted attention as promising nano-emitters due to dopant-induced properties. However, despite ample investigations on the steady-state and dynamic ...
  • A novel hot carrier-induced blue light-emitting device 

    Mutlu, S.; Erol, A.; Arslan, Engin; Özbay, Ekmel; Lisesivdin, S. B.; Tiras, E. (Elsevier, 2021-05-24)
    In this work, an InGaN/GaN multiple quantum well based Top-Hat Hot-Electron Light Emission and Lasing in a Semiconductor Heterostructure (Top-Hat HELLISH) is investigated. A heterojunction structure is designed based on ...
  • Determination of scattering mechanisms in AlInGaN/GaN heterostructures grown on sapphire substrate 

    Sonmez, F.; Arslan, Engin; Ardali, S.; Tiras, E.; Özbay, Ekmel (Elsevier, 2021-01-27)
    The electron mobility limited by different scattering mechanisms in the quaternary AlInGaN alloy grown on a GaN layer is investigated with the classical Hall measurement, which is performed at a temperature range of 12 and ...
  • Ag@SiO2-embedded InGaN/GaN nanorod array white light-emitting diode with perovskite nanocrystal films 

    Shin, Do-Y.; Kim, T.; Akyüz, Özgün; Demir, Hilmi Volkan; Lee, In-H. (Elsevier, 2021-10-28)
    White light-emitting diodes (LEDs) are great candidates for general lighting. Phosphors have commonly been used for the color conversion layers of white LEDs; however, they backscatter more than half of the down-converted ...
  • Adaptive visible and short-wave infrared camouflage using a dynamically tunable metasurface 

    Buhara, Ebru; Ghobadi, Amir; Özbay, Ekmel (Optica, 2021-10-01)
    In this Letter, a dynamically tunable metasurface, which is based on antimony trisulfide, is introduced. In this struc ture, first a metal-insulator-metal (MIM) nanocavity is optimized in a way that, upon phase change, ...

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