Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10(5) and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to ∼ 1,000 cm(2) V(-1) s(-1) obtained for a thickness of ∼ 10 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.

http://absimage.aps.org/image/MAR14/MWS_MAR14-2013-005031.pdf

Black Phosphorus Field-effect Transistors

Objective In this research paper, the brain MRI images are going to classify by considering the excellence of CNN on a public dataset to classify Benign and Malignant tumors. Materials and Methods Deep learning (DL) methods due to good performance in the last few years have become more popular for Image classification. Convolution Neural Network (CNN), with several methods, can extract features without using handcrafted models, and eventually, show better accuracy of classification. The proposed hybrid model combined CNN and support vector machine (SVM) in terms of classification and with threshold-based segmentation in terms of detection. Result The findings of previous studies are based on different models with their accuracy as Rough Extreme Learning Machine (RELM)-94.233%, Deep CNN (DCNN)-95%, Deep Neural Network (DNN) and Discrete Wavelet Autoencoder (DWA)-96%, k-nearest neighbors (kNN)-96.6%, CNN-97.5%. The overall accuracy of the hybrid CNN-SVM is obtained as 98.4959%. Conclusion In today's world, brain cancer is one of the most dangerous diseases with the highest death rate, detection and classification of brain tumors due to abnormal growth of cells, shapes, orientation, and the location is a challengeable task in medical imaging. Magnetic resonance imaging (MRI) is a typical method of medical imaging for brain tumor analysis. Conventional machine learning (ML) techniques categorize brain cancer based on some handicraft property with the radiologist specialist choice. That can lead to failure in the execution and also decrease the effectiveness of an Algorithm. With a brief look came to know that the proposed hybrid model provides more effective and improvement techniques for classification.

A Hybrid CNN-SVM Threshold Segmentation Approach for Tumor Detection and Classification of MRI Brain Images

We numerically demonstrate a tunable broadband terahertz absorber with near-unity absorption by using multilayer graphene ribbons sandwiched in a plasmonic integrated structure. By stacking slightly different widths of graphene ribbons in a sandwiched configuration, the absorption bandwidth can be increased because of the different resonant modes closely positioned together. The absorption spectrum’s center frequency can be manipulated by varying the graphene’s chemical potential, which provides a flexible way to design and optimize absorption property after fabrication. Furthermore, the structure can tolerate a wide range of incident angles, while the improved structure with graphene nanoparticles also shows polarization-independent feature. In this routine, stacking more graphene ribbons or particles with well-designed dimensions can further increase the bandwidth, as long as the metamaterial dimension satisfies the sub-wavelength condition. Therefore, our research provides an important theoretical guide for designing various graphene-based tunable broadband absorbers at terahertz, infrared, and microwave frequencies. This may have promising applications in imaging, sensing, and novel optoelectronic devices.

Tunable broadband terahertz absorber based on multilayer graphene-sandwiched plasmonic structure

Recent advances in nanofabrication technologies have spurred many breakthroughs in the field of photonic metamaterials that provide efficient ways of manipulating light-matter interaction at subwavelength scales. As one of the most important applications, photonic metamaterials can be used to implement novel optical absorbers. First the morphology engineering of various photonic metamaterial absorbers is discussed, which is highly associated with impendence matching conditions and resonance modes of the absorbers, thus directly determines their absorption efficiency, operational bandwidth, incident angle, and polarization dependence. Then, the recent achievements of various interdisciplinary applications based on photonic metamaterial absorbers, including structural color generation, ultrasensitive optical sensing, solar steam generation, and highly responsive photodetection, are reviewed. This report is expected to provide an overview and vision for the future development of photonic metamaterial absorbers and their applications in novel nanophotonic systems.

Photonic Metamaterial Absorbers: Morphology Engineering and Interdisciplinary Applications.

Strategies to improve performances of LSPR biosensing: Structure, materials, and interface modification.

As an emerging anisotropic two-dimensional (2-D) material, few-atomic-layer black phosphorus (BP) has shown some promising potentials for infrared optoelectronics. Engineering and enhancing its light-matter interaction is significant for many advanced photonic devices. In view of this, we aim to achieve extremely high infrared absorption in monolayer BP with/without subwavelength patterning. By optimizing the polarization and angle of the incident light, the dielectric thickness, and the n -type doping concentration, respectively, infrared radiation can be sufficiently coupled to optical absorption of the monolayer BP in a multiscale photonic structure. The anisotropic infrared absorbance ratios of the unpatterned monolayer BP are enhanced up to 98.2% and 96%, respectively, in inequivalent crystal directions. Moreover, monolayer BP with a design of metasurface and optimized doping can reach near-unity anisotropic infrared absorption under a smaller incident angle. This paper provides a simple and efficient scheme to trap infrared light for developing promising optoelectronic devices based on monolayer BP and potentially other anisotropic 2-D materials.

Near-Unity Anisotropic Infrared Absorption in Monolayer Black Phosphorus With/Without Subwavelength Patterning Design

Low-cost flexible plasmonic nanobump metasurfaces for label-free sensing of serum tumor marker.

Abstract Plasmonic sensing has a great potential in the portable detection of human tumor markers, among which the carcinoembryonic antigen (CEA) is one of the most widely used in clinical medicine. Traditional plasmonic and non-plasmonic methods for CEA biosensing are still not suitable for the fast developing era of Internet of things. In this study, we build up a cost-effective plasmonic immunochip platform for rapid portable detection of CEA by combining soft nanoimprint lithography, microfluidics, antibody functionalization, and mobile fiber spectrometry. The plasmonic gold nanocave array enables stable surface functionality, high sensitivity, and simple reflective measuring configuration in the visible range. The rapid quantitative CEA sensing is implemented by a label-free scheme, and the detection capability for the concentration of less than 5 ng/ml is achieved in clinical experiments, which is much lower than the CEA cancer diagnosis threshold of 20 ng/ml and absolutely sufficient for medical applications. Clinical tests of the chip on detecting human serums demonstrate good agreement with conventional medical examinations and great advantages on simultaneous multichannel detections for high-throughput and multi-marker biosensing. Our platform provides promising opportunities on low-cost and compact medical devices and systems with rapid and sensitive tumor detection for point-of-care diagnosis and mobile healthcare.

/pdf/portable-tumor-biosensing-of-serum-by-plasmonic-biochips-in-28zzgna5a8.pdf

Portable tumor biosensing of serum by plasmonic biochips in combination with nanoimprint and microfluidics

Coupling effects of surface plasmon resonance (SPR) induce changes in the wavelength, intensity, and linewidth of plasmonic modes. Here, inspired by coupling effects, we reveal an abrupt linewidth-shrinking effect in 2D gold nanohole arrays at the azimuthal angle of 45° arising from the interference of two degenerate SPR modes. We further demonstrate the biosensing capability under various excitation conditions for detecting the critical molecular biomarker of prostatic carcinoma, and achieve the maximum sensitivity at this angle. Our study not only enhances the understanding toward plasmonic resonance-linewidth shrinking, but also provides a promising strategy to greatly improve biosensing performance by light manipulation on plasmonic nanostructures.

Plasmonic resonance-linewidth shrinkage to boost biosensing

In the ultraviolet range, it is still a critical challenge to enhance and engineer light absorption inside graphene for optoelectronic applications. Here, we propose a metal-dielectric-metal plasmonic structure to achieve a high absorption ratio of ultraviolet incident light inside graphene. The absorption of ultraviolet light in single layer graphene is enhanced up to 44%, while the absorption spectrum can be tuned by optimizing the dimensions of the integrated structure. Furthermore, the structure can tolerate a wide range of incident angles, while the improved structure with aluminum nanoparticles also shows polarization-independent feature. Besides, the effect of surface oxidation on this structure is also revealed. Our research provides an important theoretical guide for designing novel optoelectronic devices based on graphene in the ultraviolet region.

Zhengying Wang

Papers

Near-Unity Anisotropic Infrared Absorption in Monolayer Black Phosphorus With/Without Subwavelength Patterning Design

Low-cost flexible plasmonic nanobump metasurfaces for label-free sensing of serum tumor marker.

Portable tumor biosensing of serum by plasmonic biochips in combination with nanoimprint and microfluidics

Plasmonic resonance-linewidth shrinkage to boost biosensing

Ultraviolet absorption band engineering of graphene by integrated plasmonic structures