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10. Metamaterial Solar Absorber Based on TiN/TiO2 Multilayer Taper Structure.

Author

M-Ramzi, Mustafa Imad, Ekşioğlu, Yasa, and Durmaz, Habibe

Subjects
METAMATERIALS, ENERGY harvesting, SOLAR cells, SOLAR energy, SURFACE plasmon resonance
Abstract

The increasing demand for renewable energy has increased in the last decade due to climate change resulting from conventional energy and solar cells become popular. The perfect absorption in solar cells can be achieved with artificially engineered materials at low cost for solar absorbers with high efficiency. A perfect ultra-broadband solar absorber can be achieved by using metamaterial (MM) based on surface plasmon resonance phenomena. We design a near-ideal ultra-broadband plasmonic MM absorber for solar energy harvesting over an ultra-broadband wavelength range (0.4–4 μ m ). The structure is made up of periodic taper arrays consisting of a thin, multilayered titanium nitride–titanium dioxide MM. The proposed structure has an absorption greater than 96% between the visible to infrared (IR) regime. It is independent of both polarization and incident angle. The large operational bandwidth, high absorption percentage, and compact thin structure combined with the strong thermal stability of metal TiN make an advantageous choice for solar thermophotovoltaics. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Lithography-free highly sensitive detection of glucose based on colloidal spheres.

Author

DURMAZ, Habibe

Subjects
*GLUCOSE analysis, *SURFACE plasmon resonance, *GLUCOSE oxidase, *GLUCOSE, *FINITE difference time domain method, *SPECTRAL sensitivity
Abstract

Diabetes has emerged as a global health crisis, with a substantial increase in prevalence and associated healthcare costs. The urgency for early diagnosis to prevent complications has fueled research into advanced biosensing technologies. Plasmonic sensors, leveraging localized surface plasmon resonance (LSPR), have gained prominence for their sensitivity. This study explores a metamaterial-based sensor platform comprising nanospheres fabricated through colloidal lithography. A comprehensive numerical and experimental analysis of the designed metamaterial-based sensor is presented, focusing on the spectral response at the resonance frequency of 535 nm. Finite-difference time-domain (FDTD) simulations reveal the field and charge distributions, enabling a systematic exploration of geometric parameters' impact on absorption resonance. The chosen optimum parameters are validated experimentally, demonstrating excellent agreement between numerical predictions and experimental outcomes. The spectral shifts occurring in the absorption spectrum of the sensor have demonstrated the molecular detection capability of very low concentrations of glucose oxidase, such as 0.001 ppm. Our approach, offering a cost-effective alternative to common fabrication methods, holds promise for the mass production of highly sensitive biosensors, providing a pathway for the development of advanced diagnostic tools for diabetes and other healthcare applications. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Metamalzeme Tabanlı İki Bantlı Mükemmel Soğurucu

Author

Aytekin, Rafettin, Durmaz, Habibe, Aytekin, Rafettin, and Durmaz, Habibe

Subjects
Engineering, Metamaterials, Surface Plasmons, Mühendislik, Physics::Optics, Nanostructure Fabrication, Perfect Absorber, nanoyapı üretimi,metamalzemeler,yüzey plazmonları,mükemmel soğurucu, nanostructure fabrication,metamaterials,surface plasmons,perfect absorber
Abstract

Son zamanlarda mükemmel soğurucular (MS), karmaşık elektriksel ve manyetik geçirgenlik özelliklerinden dolayı büyük ilgi görmüştür. Bu yapay yapıları rasyonel bir şekilde tasarlayarak, mükemmel soğurucunun empedansı, elektrik ve manyetik rezonanslarda bağımsız bir ayarlama ile boş alana eşleştirilebilir; ve böylece oluşturulan yapı, orta ve yakın kızılötesi dalga boylarında güçlü soğurmaya yol açar. Özellikle metal-dielektrik bazlı plazmonik metamalzemelerden oluşan nanoyapılar, güçlü yakın alan geliştirme, negatif kırılma indeksi ve optik gizleme gibi benzersiz optik özellikler sergiler. Bu çalışmada, metamalzeme tabanlı farklı rezonanslarda aynı anda %100’ e yakın bir soğurumla çalışan iki bantlı U şeklinde antenlerden oluşan bir MS platformu önerilmiştir. MS platformunun ince ayar mekanizması için sonlu fark zaman alanı (FDTD) simülasyonları aracılığıyla optik yanıtının geometrik parametrelere bağımlılığı sayısal olarak analiz edilmiştir. Soğurum tepkisini ve yakın alan dağılımlarının fiziksel temelleride sayısal olarak incelenmiştir. Sayısal hesaplamalarımız, ikili rezonanslarda U plazmonik anten sisteminin geniş ve kolayca erişilebilen yerel elektromanyetik alanları desteklediğini göstermektedir. Deneysel sonuçlar, teorik hesaplamalar ile oldukça uyumludur. Çift rezonanslı U şekilli antenler sahip oldukları güçlü ve erişilebilir elektromanyetik alandan dolayı güçlü yakın alan özelliklerine sahiptir ve çok sayıda spektral özellik gerektiren birçok uygulama için oldukça avantajlı olabilir. Ayrıca, önerilen U şekilli plazmonik antenlerin rezonans frekansı spektral olarak ayarlanabildiği için aktif filtreler, optik modülatörler, ultra hızlı anahtarlama cihazları, haberleşme, detektör ve biyoalgılama gibi çok çeşitli uygulamalar için de kullanılabilir., Recently, perfect absorbers (PAs) have attracted great attention due to their complex electrical permittivity and magnetic permeability properties. By rationally designing these artificial structures, the impedance of the perfect absorber can be matched to the free space with an independent adjustment in electric and magnetic resonances; and the structure thus leads to strong absorption from mid-IR to near-IR wavelength. Especially, metal-dielectric based plasmonic metamaterials in nanometer scale exhibit unique optical properties such as strong near field enhancement, negative refractive index and optical cloaking. In this study, we propose a dual-band metamaterial base PA platform consisting of U-shaped antennas with unity absorption. We numerically analyzed the dependence of the optical response on geometric parameters through finite difference time domain (FDTD) simulations for the fine tuning mechanism of the PA platform. The physical basis of the absorption response and near-field distributions of these nanoscale antennas were also studied numerically. Our numerical calculations show that U-shaped plasmonic antenna system supports large and easily accessible local electromagnetic fields. Experimental and theoretical results are found to be in good aggrement. U-shaped antennas with dual resonances with large and accessible electromagnetic fields can be highly advantageous for a wide variety of applications that require a large number of spectral features with strong near field properties. In addition, since the resonance frequency of the proposed U-shaped plasmonic antennas can be adjusted spectrally, they can also be used for a wide variety of applications such as active filters, optical modulators, ultra-fast switching devices, communication, detectors and biosensing.

Published
2022

16. Detection of 2,4-Dinitrotoluene by Metal-Graphene Hybrid Plasmonic Nanoantennas with a Golden Ratio Rectangular Resonator.

Author

Erturan, Ahmet Murat, Gultekin, Seyfettin Sinan, and Durmaz, Habibe

Subjects
GOLDEN ratio, OPTICAL antennas, CHEMICAL fingerprinting, RESONATORS, OPTIMIZATION algorithms, PLASMONICS, NITRO compounds
Abstract

Plasmonic nanoantenna arrays have become increasingly popular for the detection of chemical molecules, biomolecules, viruses, and agents. In this study, our objective was to detect explosive-based 2,4-dinitrotoluene (2,4-DNT) with a metal-graphene hybrid plasmonic rectangular nanoantenna with a golden ratio size formed by choosing two consecutive numbers from the Fibonacci series. The golden rectangular resonator provides nearly perfect absorption without the need for impedance matching calculations and complex optimisation algorithms. In surface enhanced infrared absorption (SEIRA) applications, the internal losses of metallic nanostructures degrade their sensing performance. To improve performance sensitivity, graphene with high electrical conductivity and electrical tunability was used. The spectral fingerprints of 2,4 DNT at 6300 nm, 6580 nm, and 7500 nm were enhanced with a metal-graphene hybrid structure. The biosensor platform introduced, by combining the graphene and nanoantennas with a golden ratio and by adjusting the Fermi energy level of graphene, can be beneficial for highly sensitive tunable biosensors for a broad spectrum to identify the molecular fingerprints of specific biomolecules. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Improvement of Response Time and Heat-Transfer Capacity of Metamaterial Absorber for Terahertz Detector Applications

Author

Tantiwanichapan, Khwanchai and Durmaz, Habibe

Abstract

We have introduced a THz metamaterial absorber (MMA) system that consists of a metal disk antenna connected to successive dielectric and metal layers via a metal rod. The heat-transfer speed and capacity of the proposed platform with a metal rod inserted through the dielectric layer have been numerically studied for the first time in this work. The proposed THz MMA system can improve the heat-transfer capacity of 0.7 K/s compared to without a metal rod situation. The simulation proves that heat transfer can be achieved in the proposed absorber less than $10 ~\mu \text{s}$ times compared to without a metal rod case. The simulation results indicate that the absorption strength of the MMA is almost independent of the rod depth. This detector system will be remarkably beneficial for imaging applications where fast heat-signal conversion is necessary.

Published
2023
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22. Multi-Band Plasmonic Platform Utilizing UT-Shaped Graphene Antenna Arrays

Author

Koch Institute for Integrative Cancer Research at MIT, Cetin, Arif Engin, Ekşioğlu, Yasa, Durmaz, Habibe, Koch Institute for Integrative Cancer Research at MIT, Cetin, Arif Engin, Ekşioğlu, Yasa, and Durmaz, Habibe

Abstract

In this work, we introduce a plasmonic platform based on UT-shaped graphene antenna arrays. The proposed multi-resonant platform shows three different resonances, which can be independently tuned. The physical origin of these modes is shown with finite-difference time-domain (FDTD) nearfield distribution analyses, which are used to statically tune each resonance wavelength via the geometrical parameters, corresponding to different nearfield localization. We achieve statistical tuning of multiple resonances also by changing the number of graphene layers. Another static tuning of the optical response of the UT-shaped graphene antenna is achieved via the chemical potential and the relaxation time. Keywords Surface plasmon, Graphene plasmonics, Multi-band

Published
2018

31. Strain Engineered SiGe Multiple-Quantum-Well Nanomembranes for Far-Infrared Intersubband Device Applications

Author

Sookchoo, Pornsatit, Sudradjat, Faisal F., Kiefer, Arnold M., Durmaz, Habibe, Paiella, Roberto, and Lagally, Max G.

Abstract

SiGe/Si quantum wells are of great interest for the development of Group-IV THz quantum cascade lasers. The main advantage of Group-IV over III–V materials such as GaAs is that, in the former, polar phonon scattering, which significantly diminishes the efficiency of intersubband light emission, is absent. However, for SiGe/Si multiple-quantum-well structures grown on bulk Si, the lattice mismatch between Si and Ge limits the critical thickness for dislocation formation and thus the number of periods that can be grown. Similarly, the use of composition-graded SiGe films as a lattice-matched substrate leads to the transfer of dislocations from the graded buffer substrate into the quantum wells, with a consequent decrease in light emission efficiency. Here we instead employ nanomembrane strain engineering to fabricate dislocation-free strain relaxed substrates, with lattice constants that match the average lattice constants of the quantum wells. This procedure allows for the growth of many periods with excellent structural properties. The samples in this work were grown by low-pressure chemical vapor deposition and characterized viahigh-resolution X-ray diffraction and far-infrared transmission spectroscopy, showing narrow intersubband absorption features indicative of high crystalline quality.

Published
2013
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32. Terahertz and mid-infrared photodetectors based on intersubband transitions in novel materials systems

Author

Durmaz, Habibe

Subjects
Electrical engineering, GaN detectors, Intersubband photodetectors, MiR photodetectors, SiGe detectors, SiGe strain engineering, THz photodetectors
Abstract

The terahertz (THz) and mid-infrared (MIR) spectral regions have many potential applications in the industrial, biomedical, and military sectors. Yet, a wide portion of this region of the electromagnetic spectrum (particularly the THz range) is still relatively unexplored, due mainly to the absence of suitable sources and photodetectors, related to the lack of practical semiconductor materials with adequately small band gap energies. Intersubband transitions (ISBTs) between quantized energy states in quantum heterostructures provide tunable wavelengths over a broad spectral range including the THz region, by choosing appropriate layer thicknesses and compositions. This work focuses on the development of THz and MIR Quantum Well Infrared Photodetectors (QWIPs) based on ISBTs in GaN/AlGaN and Si/SiGe heterostructures. Due to their large optical phonon energies, GaN materials allow extending the spectral reach of existing far-infrared photodetectors based on GaAs, and may enable higher-temperature operation. In the area of MIR optoelectronic devices, I have focused on developing QWIPs based on ISBTs in Si/SiGe heterostructures in the form of on strain-engineered nanomembranes. Due to their non-polar nature, these materials are free from reststrahlen absorption and ultrafast resonant electron/phonon scattering, unlike traditional III-V semiconductors. Therefore, Si/SiGe quantum wells (QWs) are also promising candidates for high-temperature high-performance ISB device operation (particularly in the THz region), with the additional advantage of direct integration with CMOS technology. In this thesis work, numerical modeling is used to design the active region of the proposed devices, followed by sample fabrication and characterization based on lock-in step-scan Fourier transform infrared spectroscopy. Three specific QWIP devices have been developed. The first is a III-nitride THz QWIP based on a novel double-step QW design in order to alleviate the material limitations provided by the intrinsic electric fields of GaN/AlGaN heterostructures. Next, I have developed a THz GaN/AlGaN QWIP grown on semi-polar (202 ̅1 ̅) GaN, where the detrimental effects of the internal fields are almost completely eliminated. Finally, I have demonstrated a Si/SiGe MIR QWIP based on a novel fabrication approach, where nanomembrane strain engineering is used to address the materials quality issues normally found in SiGe QWs. Promising photodetector performance is obtained in all cases.

Published
2016

33. Dual band perfect absorber based on metamaterials

Author

Habibe Durmaz, Rafettin Aytekin, Aytekin, Rafettin, and Durmaz, Habibe

Subjects
Mükemmel Soğurucu, Materials science, Metamaterials, Yüzey Plazmonları, Surface Plasmons, Nanoyapı Üretimi, Nanostructure Fabrication, Perfect Absorber, Metamalzemeler
Abstract

Son zamanlarda mükemmel soğurucular (MS), karmaşık elektriksel ve manyetik geçirgenlik özelliklerinden dolayı büyük ilgi görmüştür. Malzemenin ve geometrinin doğru oranlarda seçilmesiyle MS’ nin empedansı boş uzaya eşleştirilebilir; böylece geniş elektromanyetik spektrumda güçlü soğurum elde edilebilir. Özellikle metal-dielektrik bazlı plazmonik metamalzemelerden oluşan nanoyapılar, güçlü yakın alan geliştirme, negatif kırılma indeksi ve optik gizleme gibi benzersiz optik özellikler sergiler. Bu çalışmada, metamalzeme tabanlı farklı rezonanslarda aynı anda %100’ e yakın bir soğurumla çalışan iki bantlı U şeklinde antenlerden oluşan bir MS platformu önerilmiştir. MS platformunun ince ayar mekanizması için sonlu fark zaman alanı (FDTD) simülasyonları aracılığıyla spektral yanıtının geometrik parametrelere bağımlılığı sayısal olarak analiz edilmiştir. Soğurum tepkisini ve yakın alan dağılımlarının fiziksel temelleride sayısal olarak incelenmiştir. Sayısal hesaplamalarımız, ikili rezonanslarda U plazmonik anten sisteminin geniş ve kolayca erişilebilen yerel elektromanyetik alanları desteklediğini göstermektedir. Deneysel sonuçlar, teorik hesaplamalar ile oldukça uyumlu olduğu gösterilmiştir. Çift rezonanslı U şekilli antenler sahip oldukları güçlü ve erişilebilir elektromanyetik alandan dolayı güçlü yakın alan özelliklerine sahiptir ve çok sayıda spektral özellik gerektiren birçok uygulama için oldukça avantajlı olabilir. Ayrıca, önerilen U şekilli plazmonik antenlerin rezonans frekansı spektral olarak ayarlanabildiği için aktif filtreler, optik modülatörler, ultra hızlı anahtarlama cihazları, haberleşme, detektör ve biyoalgılama gibi çok çeşitli uygulamalar için de kullanılabilir. Recently, perfect absorbers (PAs) have attracted great attention due to their complex electrical permittivity and magnetic permeability properties. By choosing the right ratio of the material and geometry the impedance of the perfect absorber can be matched to to the free space; therefore, strong absorption in a wide range of electromagnetic spectrum. Especially, metal-dielectric based plasmonic metamaterials in nanometer scale exhibit unique optical properties such as strong near field enhancement, negative refractive index and optical cloaking. In this study, we propose a dual-band metamaterial base PA platform consisting of U-shaped antennas with unity absorption. The finite difference time domain (FDTD) method was used to numerically analyze the spectral response dependence on geometric parameters to fine tune the mechanism of the PA platform. The physical basis of the absorption response and near-field distributions of these nanoscale antennas were also studied numerically. Our numerical calculations show that U-shaped plasmonic antenna system supports large and easily accessible local electromagnetic fields. Experimental and theoretical results are found to be in good aggrement. U-shaped antennas with dual resonances with strong electromagnetic fields can be highly advantageous for a wide variety of applications that require a large number of spectral features with strong near field properties. In addition, since the resonance frequency of the proposed U-shaped plasmonic antennas can be adjusted spectrally, they can also be used for a wide variety of applications such as active filters, optical modulators, ultra-fast switching devices, communication, detectors and biosensing.

Published
2021

34. Graphene terahertz plasmons: A combined transmission spectroscopy and raman microscopy study

Author

Xuanye Wang, Habibe Durmaz, Yuyu Li, Anna K. Swan, Khwanchai Tantiwanichapan, Roberto Paiella, RTEÜ, Mühendislik ve Mimarlık Fakültesi, Elektrik-Elektronik Mühendisliği Bölümü, and Durmaz, Habibe

Subjects
Materials science, Silicon, Terahertz radiation, chemistry.chemical_element, Terahertz photonics, 02 engineering and technology, 01 natural sciences, law.invention, symbols.namesake, law, 0103 physical sciences, Microscopy, Polariton, Electrical and Electronic Engineering, 010306 general physics, Absorption (electromagnetic radiation), Plasmon, business.industry, Graphene, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, chemistry, symbols, Optoelectronics, Plasmonics, 0210 nano-technology, business, Raman spectroscopy, Biotechnology
Abstract

Paiella, Roberto/0000-0002-7183-6249; Swan, Anna/0000-0002-3978-7993 WOS: 000408077800018 Graphene provides a promising materials platform for fundamental studies and device applications in plasmonics. Here we investigate the excitation of THz plasmon polaritons in large-area graphene samples on standard oxidized silicon substrates, via diffractive coupling from an overlying periodic array of metallic nanoparticles. Pronounced plasmonic absorption features are measured, whose frequencies can be tuned across a large portion of the THz spectrum by varying the array period. At the same time, the ability to tune these resonances actively via electrostatic doping is found to be strongly limited by the presence of large carrier density variations across the sample area induced by the underlying SiO2, which are measured directly by Raman microscopy. These results highlight the importance of minimizing charge "puddles" in graphene plasmonic devices, e.g., through the use of more inert substrates, in order to take full advantage of their expected dynamic tunability for applications in THz optoelectronics. National Science FoundationNational Science Foundation (NSF) [DMR-1308659]; Royal Thai Government Fellowship; Turkey Ministry of Education Fellowship; Division of Materials ResearchNational Science Foundation (NSF)NSF - Directorate for Mathematical & Physical Sciences (MPS) [1411008] Funding Source: National Science Foundation This work was supported by the National Science Foundation under Grant DMR-1308659. K.T. and H.D. acknowledge partial support by a Royal Thai Government Fellowship and by a Turkey Ministry of Education Fellowship, respectively.

Published
2017

35. GaN terahertz photodetectors for the reststrahlen Gap of intersubband optoelectronics

Author

Roberto Paiella, Denis Nothern, Gordie Brummer, Theodore D. Moustakas, Habibe Durmaz, RTEÜ, Mühendislik ve Mimarlık Fakültesi, Elektrik-Elektronik Mühendisliği Bölümü, and Durmaz, Habibe

Subjects
010302 applied physics, Materials science, business.industry, Terahertz radiation, Photodetector, Gallium nitride, 02 engineering and technology, Semiconductor device, Substrate (electronics), 021001 nanoscience & nanotechnology, 01 natural sciences, Photon counting, chemistry.chemical_compound, chemistry, 0103 physical sciences, Optoelectronics, 0210 nano-technology, business, Absorption (electromagnetic radiation), Quantum well
Abstract

Conference on Lasers and Electro-Optics (CLEO) -- MAY 14-19, 2017 -- San Jose, CA WOS: 000427296202271 Terahertz intersubband photodetectors are developed based on GaN/AlGaN quantum wells grown on a semi-polar GaN substrate, covering the frequency range that is fundamentally inaccessible to existing III-V semiconductor devices due to Reststrahlen absorption. IEEE NSFNational Science Foundation (NSF) [ECS-0824116] This work was partly supported by NSF under Grant ECS-0824116.

Published
2017

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