scholarly journals An Effort Towards Full Graphene Photodetectors

2020 ◽  
Author(s):  
Farhad Larki ◽  
Yaser Abdi ◽  
Parviz Kameli ◽  
Hadi Salamati
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Device Fabrication ◽  
Monolayer Graphene ◽  
High Quality ◽  
Promising Candidate ◽  
2D System ◽  
Proper Design ◽  
Pros And Cons ◽  
Electro Magnetic

AbstractGraphene as a truly 2-dimensional (2D) system is a promising candidate material for various optoelectronic applications. Implementing graphene as the main building material in ultra-broadband photodetectors has been the center of extensive research due to its unique absorption spectrum which covers most of the electro-magnetic spectra. However, one of the main challenges facing the wide application of pure graphene photodetectors has been the small optical absorption of monolayer graphene. Although novel designs were proposed to overcome this drawback, they often need complicated fabrication processes in order to integrate with the graphene photodetector. In this regard, fabrication of purely graphene photodetectors is a promising approach towards the manufacturing of simple, inexpensive, and high photosensitive devices. The fabrication of full graphene photodetectors (FGPDs) is mainly based on obtaining an optimal technique for the growth of high quality graphene, modification of electronic and optical properties of the graphene, appropriate techniques for transfer of graphene from the grown substrate to the desire position, and a proper design for photodetection. Therefore, the available states of the art techniques for each step of device fabrication, along with their pros and cons, are reviewed and the possible approaches for optimization of FGPDs have been proposed.

scholarly journals High Quality Factor, High Sensitivity Metamaterial Graphene—Perfect Absorber Based on Critical Coupling Theory and Impedance Matching

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 95 ◽  
Author(s):  
Chunlian Cen ◽  
Zeqiang Chen ◽  
Danyang Xu ◽  
Liying Jiang ◽  
Xifang Chen ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Quality Factor ◽  
Near Infrared ◽  
Coupling Effect ◽  
Impedance Matching ◽  
High Quality Factor ◽  
Monolayer Graphene ◽  
Perfect Absorber ◽  
Critical Coupling ◽  
High Quality

By means of critical coupling and impedance matching theory, we have numerically simulated the perfect absorption of monolayer graphene. Through the critical coupling effect and impedance matching, we studied a perfect single-band absorption of the monolayer graphene and obtained high quality factor (Q-factor = 664.2) absorption spectrum which has an absorbance close to 100% in the near infrared region. The position of the absorption spectrum can be adjusted by changing the ratio between the radii of the elliptic cylinder air hole and the structural period. The sensitivity of the absorber can be achieved S = 342.7 nm/RIU (RIU is the per refractive index unit) and FOM = 199.2 (FOM is the figure of merit), which has great potential for development on biosensors. We believe that our research will have good application prospects in graphene photonic devices and optoelectronic devices.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

Quantum optics with nitrogen-vacancy centres in diamond

2017 ◽  
Author(s):  
Yiwen Chu ◽  
Mikhail D. Lukin
Keyword(s):  
Optical Properties ◽  
Quantum Information ◽  
Solid State ◽  
Quantum Optics ◽  
Quantum States ◽  
Nitrogen Vacancy ◽  
Common Theme ◽  
External Effects ◽  
Promising Candidate ◽  
Optical Photons

A common theme in the implementation of quantum technologies involves addressing the seemingly contradictory needs for controllability and isolation from external effects. Undesirable effects of the environment must be minimized, while at the same time techniques and tools must be developed that enable interaction with the system in a controllable and well-defined manner. This chapter addresses several aspects of this theme with regard to a particularly promising candidate for developing applications in both metrology and quantum information, namely the nitrogen-vacancy (NV) centre in diamond. The chapter describes how the quantum states of NV centres can be manipulated, probed, and efficiently coupled with optical photons. It also discusses ways of tackling the challenges of controlling the optical properties of these emitters inside a complex solid state environment.

scholarly journals Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4233-4252
Author(s):  
Yael Gutiérrez ◽  
Pablo García-Fernández ◽  
Javier Junquera ◽  
April S. Brown ◽  
Fernando Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Phase Change Materials ◽  
Two Dimensional ◽  
Active Materials ◽  
Promising Candidate ◽  
Plasmonic Structures ◽  
Resonance Tuning ◽  
The Many ◽  
Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

Microstructural and optical properties of high-quality Mg–Zn oxide thin films

2021 ◽  
Vol 127 ◽  
pp. 105690
Author(s):  
A. Sáenz-Trevizo ◽  
D. Kuchle-Mena ◽  
P. Pizá-Ruiz ◽  
P. Amézaga-Madrid ◽  
O. Solís-Canto ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Oxide Thin Films ◽  
High Quality

Tailoring the optical properties of tin oxide thin films via gamma irradiation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ateyyah M. Al-Baradi ◽  
Ahmed A. Atta ◽  
Ali Badawi ◽  
Saud A. Algarni ◽  
Abdulraheem S. A. Almalki ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Gamma Irradiation ◽  
Tin Oxide ◽  
Free Charge Carrier ◽  
Oxide Thin Films ◽  
Dispersion Parameters ◽  
Absorption Spectrum Fitting ◽  
Spectrum Fitting

Abstract In the current work, the optical properties of tin oxide thin films have been tailored via gamma irradiation for energy applications. The effect of Gamma radiation (50, 100, 150, 200 and 250 kGy) on the microstructural, absorption and oscillator parameters of SnO2 thin films has been investigated. XRD results reveal that the SnO2 films have the symmetry of the space group P42/mnm belonging to the tetragonal system. The crystallite size of γ-irradiated SnO2 thin film slightly increases as the irradiation dose increases. The allowed optical band gaps are estimated by applying various methods such as Tauc’s method, derivation of absorption spectrum fitting and absorption spectrum fitting approaches. The dispersion parameters are extracted from the dispersion curve of the real part of the refractive index. The single-effective-oscillator and Drude models for free charge carrier absorption are applied to obtain the dispersion parameters before and after γ-irradiation.

Dependence of Scintillators Optical Properties on Intrinsic Structural Defects

1994 ◽  
Vol 348 ◽  
Author(s):  
N.V. Kilassen
Keyword(s):  
Plastic Deformation ◽  
Optical Properties ◽  
Crystal Growth ◽  
Spectral Distribution ◽  
Light Output ◽  
Structural Defects ◽  
High Quality ◽  
Intrinsic Defects ◽  
Distribution Kinetics ◽  
Wide Range

ABSTRACTThe studies of the dependence of the optical properties of various scintillators on intrinsic structural defects have been reviewed. The greater part of the review is devoted to the defects introduced by plastic deformation. A wide range of variations in the light output, spectral distribution, kinetics and other properties has been observed. These defects can be induced during crystal growth, annealing, processing, etc. The proper regulation of the superstructure of intrinsic defects can ensure the production of high quality scintillators having required properties.

Material and optical properties of GaAs grown on (001) Ge/Si pseudo-substrate

2004 ◽  
Vol 809 ◽  
Author(s):  
Yves Chriqui ◽  
Ludovic Largeau ◽  
Gilles Patriarche ◽  
Guillaume Saint-Girons ◽  
Sophie Bouchoule ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dislocation Density ◽  
High Speed ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Lattice Parameter ◽  
Photoluminescence Intensity ◽  
High Quality ◽  
Light Emitting ◽  
Thermal Expansion Coefficients

ABSTRACTOne of the major challenges during recent years was to achieve the compatibility of III-V semiconductor epitaxy on silicon substrates to combine opto-electronics with high speed circuit technology. However, the growth of high quality epitaxial GaAs on Si is not straightforward due to the intrinsic differences in lattice parameters and thermal expansion coefficients of the two materials. Moreover, antiphase boundaries (APBs) appear that are disadvantageous for the fabrication of light emitting devices. Recently the successful fabrication of high quality germanium layers on exact (001) Si by chemical vapor deposition (CVD) was reported. Due to the germanium seed layer the lattice parameter is matched to the one of GaAs providing for excellent conditions for the subsequent GaAs growth. We have studied the material morphology of GaAs grown on Ge/Si PS using atomic layer epitaxy (ALE) at the interface between Ge and GaAs. We present results on the reduction of APBs and dislocation density on (001) Ge/Si PS when ALE is applied. The ALE allows the reduction of the residual dislocation density in the GaAs layers to 105 cm−2 (one order of magnitude as compared to the dislocation density of the Ge/Si PS). The optical properties are improved (ie. increased photoluminescence intensity). Using ALE, light emitting diodes based on strained InGaAs/GaAs quantum well as well as of In(Ga)As quantum dots on an exactly oriented (001) Ge/Si pseudo-substrate were fabricated and characterized.

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