1,720,980 research outputs found
Nanocrystalline thin film gas sensors
No full textThe term sensor comes from the Latin word ‘sentire’ which means to perceive (Sze in Semiconductor sensors. Wiley, New York, 1994 [1]). In electronics sensors are a type of devices that converts some non-electrical input parameter (which we want to measure) into electrical signals having some correlation with the magnitude and nature of the input. Sensors have invaded every sphere of modern industry. In industrial automation, consumer electronics, automobile, space-exploration, medical sector, sensors are everywhere. One of the chief applications of sensors is for the detection of gases and chemical vapors
Fundamentals of quantum theory
No full textWe live in a macroscopic world surrounded by macroscopic objects, which adhere to the laws of classical mechanics and are very comfortable with it. From the trajectory of a humble pebble thrown into a pond and the ripples thus created by it, to the motion of the great planets can all be quite satisfactorily explained within the domain of classical physics. However, apart from this macroscopic scale, there exist numerous other phenomena around us, especially on the microscopic scale, which seem to defy most conventional “common-sense” beliefs. The key to the understanding of the workings of this amazing microscopic world lies with quantum physics
Basic solid-state physics and crystallography
No full textThe physics and structure of solid materials is an extremely vast and interesting field of study. In this chapter, we would only look at the basic concepts of solid-state physics, with an outlook toward nanocrystalline solids
Introduction
No full textOver the last 15–20 years there has been a lot of buzz surrounding the word “nanotechnology” [1, 2, 3, 4, 5, 6, 7]. A lot is being printed in the press and being aired in the media regarding how this new technology is changing the world around us with myriad applications. It is already touching the everyday lives of people in various avatars such as nanoparticles containing sunscreen lotions, dirt-resistant glass/paint with nanocoatings, the lab on a chip (also known as the micro testing and analyzing system; µ-TAS in short), and the various nanocomposite materials. This chapter looks to introduce the readers to what nanotechnology is about
Semi-analytical modeling of Ag and Au nanoparticles and fullerene (C60) embedded gate oxide compound semiconductor MOSFET memory devices
Get PDFIn this paper we present an analytical simulation study of Non-volatile MOSFET memory devices with Ag/Au nanoparticles/fullerene (C60) embedded gate dielectric stacks. We considered a long channel planar MOSFET, having a multilayer SiO2-HfO2 (7.5 nm)-Ag/Au nc/C60 embedded HfO2 (6 nm)-HfO2 (30 nm) gate dielectric stack. We considered three substrate materials GaN, InP and the conventional Si substrate, for use in such MOSFET NVM devices. From a semi-analytic solution of the Poisson equation, the potential and the electric fields in the substrate and the different layers of the gate oxide stack were derived. Thereafter using the WKB approximation, we have investigated the Fowler-Nordheim tunneling currents from the Si inversion layer to the embedded nanocrystal states in such devices. From our model, we simulated the write-erase characteristics, gate tunneling currents, and the transient threshold voltage shifts of theMOSFET NVM devices. The results from our model were compared with recent experimental results for Au nc and Ag nc embedded gate dielectric MOSFET memories. From the studies, the C60 embedded devices showed faster charging performance and higher charge storage, than both the metallic nc embedded devices. The nc Au embedded device displayed superior characteristics compared to the nc Ag embedded device. From the model GaN emerged as the overall better substrate material than Si and InP in terms of higher threshold voltage shift, lesser write programming voltage and better charge retention capabilities.Fil: Sengupta, Amretashis. Jadavpur University; India. Indian Institute of Science; IndiaFil: Sarkar, Chandan Kumar. Jadavpur University; IndiaFil: Requejo, Felix Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin
Introduction to Nano: Basics to Nanoscience and Nanotechnology
No full textThis books covers the basics of nanotechnology and provides a solid understanding of the subject. Starting from a brush-up of the basic quantum mechanics and materials science, the book helps to gradually build up understanding of the various effects of quantum confinement, optical-electronic properties of nanoparticles, and major nanomaterials. The book covers the various physical, chemical and hybrid methods of nanomaterial synthesis and nanofabrication as well as advanced characterization techniques. It includes chapters on the various applications of nanoscience and nanotechnology. It is written in a simple form, making it useful for students of physical and material sciences
Introduction to Nano: Basics to Nanoscience and Nanotechnology
No full textThis books covers the basics of nanotechnology and provides a solid understanding of the subject. Starting from a brush-up of the basic quantum mechanics and materials science, the book helps to gradually build up understanding of the various effects of quantum confinement, optical-electronic properties of nanoparticles, and major nanomaterials. The book covers the various physical, chemical and hybrid methods of nanomaterial synthesis and nanofabrication as well as advanced characterization techniques. It includes chapters on the various applications of nanoscience and nanotechnology. It is written in a simple form, making it useful for students of physical and material sciences
Electronic and optical properties of SnX<sub>2</sub>(X=S, Se) - InSe van der Waal's heterostructures from first-principle calculations
Get PDFIn this work from first-principles simulations we investigate bilayer van der Waals heterostructures (vdWh) of emerging 2-dimensional (2D) optical materials SnS 2 and SnSe 2 with monolayer InSe. With density functional theory (DFT) calculations, we study the structural, electronic, optical and carrier transport properties of the SnX 2 (X=S,Se)-InSe vdWh. Calculations show SnX 2 -InSe in its most stable stacking form (named AB-1) to be a material with a small (0.6- 0.7eV) indirect band-gap. The bilayer vdWh shows broad spectrum optical response, with number of peaks in the infra-red to visible region. In terms of carrier transport properties, asymmetry in conductance was observed with respect to the transport direction and electron and hole transmission. The findings are promising from the viewpoint of nanoelectronics and photonics
Atomistic study of electrostatics and carrier transport properties of CNT@MS2 (M = Mo, W) and CNT@BN core–shell nanotubes
No full textIn this work we present an ab initio study of electronic properties of one-dimensional (1D) core–shell nanostructures made of MS2 (MoS2, WS2) or BN armchair nanotube encapsulated carbon nanotubes (CNT). With local density approximation in density functional theory we calculate the band structure, carrier effective masses, various fundamental electrostatic features and optical absorption in such core–shell tubes. The carrier transport in these structures is important for nanoelectronics applications and is studied with the Green’s function formalism. Simulations show a moderate indirect band gap in the core–shell CNT@MS2 tubes, while the CNT@BN shows metallic nature. The varying chirality of CNT strongly affects the carrier effective masses of the CNT@MS2 structure. Electron density is found to be much more localized near the atom cores and stronger in magnitude for the CNT@BN, while the W atoms show a more prominent electron–gas presence around them than Mo atoms as found in the electron localization functions. In the CNT@MS2 systems, the electrostatic difference potential indicates a drive to transfer charge from the metal to the S atoms in the shell. In terms of optical absorption, a strong and sharper peak is observed around 6 eV for the CNT@BN compared to a more broad absorption spectra of the CNT@MS2. Metallic transmission spectra are seen for CNT@BN, while CNT@MS2 shows non-metallic transport but with a larger number of transmission states near Fermi level. The electronic and optical properties and its possible tuning in the core–shell structures can be useful in various applications such as shielded interconnects, logic switches and optoelectronics
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