Metin Kayci

Bio: Metin Kayci is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Tracking (particle physics) & Particle. The author has an hindex of 3, co-authored 6 publications receiving 3583 citations.

Ultrasensitive photodetectors based on monolayer MoS2.

Abstract: A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.

Electron spin resonance of nitrogen-vacancy defects embedded in single nanodiamonds in an ABEL trap.

Abstract: Room temperature optically detected magnetic resonance of a single quantum object with nanoscale position control is an outstanding challenge in many areas, particularly in the life sciences. We introduce a novel approach to control the nitrogen-vacancy (NV) centers hosted in a single fluorescent nanodiamond (FND) for which an anti-Brownian electrokinetic trap (ABEL) performs the position control and an integrated radiofrequency (RF) circuit provides enhanced magnetic flux density for ensemble spin-state control simultaneously. We demonstrate static magnetic field sensing in platforms compatible with ABEL trap. With the advances in the synthesis and functionalization of stable arbitrarily small FNDs, we foresee the use of our device for the trapping and manipulation of single molecular-sized FNDs in aqueous solution.

Single florescent nanodiamond in a three dimensional ABEL trap.

Abstract: Three dimensional single particle trapping and manipulation is an outstanding challenge in various fields ranging from basic physics to life sciences. By monitoring the response of a trapped particle to a designed environment one can extract its characteristics. In addition, quantum dynamics of a spatially scanned well-known particle can provide environmental information. Precise tracking and positioning of such a particle in aqueous environment is crucial task for achieving nano-scale resolution. Here we experimentally demonstrate three dimensional ABEL trap operating at high frequency by employing a hybrid approach in particle tracking. The particle location in the transverse plane is detected via a scanning laser beam while the axial position is determined by defocused imaging. The scanning of the trapped particle is accomplished through a nano positioning stage integrated to the trap platform.

Supplementary information for Ultrasensitive photodetectors based on monolayer MoS2

Abstract: We studied the influence of different pre-deposition surface treatments and contact materials on the photoresponse decay. We find that different surface cleaning treatments can be used to reduce the decay time. This can be explained by differences in resulting level of hydrophobicity of the functionalized SiO

Nanoscale Magnetometry with Single Fluorescent Nanodiamonds Manipulated in an Anti-Brownian Electrokinetic Trap

Abstract: Studies on single-molecule spectroscopy and nanoscale detection have been remarkably driven by an interest to reveal quantum and conformational states of single particles, the intra-molecular dynamics and their response to physical observables hidden by ensemble level measurements. A straightforward practice used in enhancing the signal from single particles is either to immobilize them on an engineered substrate or to embed them in a solid matrix. Given that the biophysical properties of the host environment introduce new perturbations and the particles will not behave as in their native environment, such approaches are inefficient to reflect the real dynamics. Therefore, recent advances in the field of single-molecule have led to a renewed interest in novel trapping methods, increased efforts into the development of promising tools for extended investigation, and the manipulation of solution-phase bio-molecules in real time. Despite the variety of successful passive trapping techniques, precise manipulation through non-perturbative forces is a big challenge for nano-sized particles. Such techniques either exert high power to the sample or compel special operating conditions disturbing the native environment. Therefore, an active trapping scheme guiding non-perturbative forces can break the trade-off between the particle size and the excreted power. This dissertation presents the development of an active trapping set-up using non-perturbative electrokinetic feedback and demonstrates its performance on nano-sized single particles for aims in biophysics. The essential theme is the engineering aspect of the technique, including the feedback configurations for various fluidic devices, the corresponding particle tracking schemes and the integration of the trapping platform to an integrated circuit pattern for advanced manipulation aims. The second theme is on specialized single fluorescence nanodiamonds (FNDs) as scanning magnetometer in fluidics. The implemented active trapping tool is employed for the manipulation of a rotationally free single FND to detect the localized magnetic field through an optically detected magnetic resonance (ODMR) spectrum. While the laser beam used in particle tracking can serve in optical excitation, an external radio frequency (RF) source is not sufficient to achieve microwave manipulation. Therefore, an RF antenna is designed to transmit the microwave signal to the proximity of the trapping chamber for electron spin resonance (ESR) spectroscopy. A nanostage positioning controller introduces scanning ability to the sample plane, in relative position of the trapped particle, in order to map the distribution of the detected fields over a fluidic volume. As FNDs are also sensitive to many other physical quantities, nanoscale single particle trapping and diamond photonics linkages are realized in this work, which provide an outstanding alternative for detection and imaging in complex fluidic environments that are closed to AFM-like physically supported probes.

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Photodetectors based on graphene, other two-dimensional materials and hybrid systems

Abstract: Graphene and other two-dimensional materials, such as transition metal dichalcogenides, have rapidly established themselves as intriguing building blocks for optoelectronic applications, with a strong focus on various photodetection platforms The versatility of these material systems enables their application in areas including ultrafast and ultrasensitive detection of light in the ultraviolet, visible, infrared and terahertz frequency ranges These detectors can be integrated with other photonic components based on the same material, as well as with silicon photonic and electronic technologies Here, we provide an overview and evaluation of state-of-the-art photodetectors based on graphene, other two-dimensional materials, and hybrid systems based on the combination of different two-dimensional crystals or of two-dimensional crystals and other (nano)materials, such as plasmonic nanoparticles, semiconductors, quantum dots, or their integration with (silicon) waveguides

Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides

Abstract: The electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties are reviewed. Recent advances in the development of atomically thin layers of van der Waals bonded solids have opened up new possibilities for the exploration of 2D physics as well as for materials for applications. Among them, semiconductor transition metal dichalcogenides, MX2 (M = Mo, W; X = S, Se), have bandgaps in the near-infrared to the visible region, in contrast to the zero bandgap of graphene. In the monolayer limit, these materials have been shown to possess direct bandgaps, a property well suited for photonics and optoelectronics applications. Here, we review the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties.

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Abstract: We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides

Abstract: With advances in exfoliation and synthetic techniques, atomically thin films of semiconducting transition metal dichalcogenides have recently been isolated and characterized. Their two-dimensional structure, coupled with a direct band gap in the visible portion of the electromagnetic spectrum, suggests suitability for digital electronics and optoelectronics. Toward that end, several classes of high-performance devices have been reported along with significant progress in understanding their physical properties. Here, we present a review of the architecture, operating principles, and physics of electronic and optoelectronic devices based on ultrathin transition metal dichalcogenide semiconductors. By critically assessing and comparing the performance of these devices with competing technologies, the merits and shortcomings of this emerging class of electronic materials are identified, thereby providing a roadmap for future development.