High voltage 4H-SiC Schottky barrier diodes

Characteristics of 4H-SiC Schottky barrier diodes with breakdown voltages up to 1000 V are reported for the first time. The diodes showed excellent forward I-V characteristics, with a forward voltage drop of 1.06 V at an on-state current density of 100 A/cm². The specific on-resistance for these diodes was found to be low (2×10 ^-3 Ω-cm² at room temperature) and showed a T ^1.6 variation with temperature. Titanium Schottky barrier height was determined to be 0.99 eV independent of the temperature. The breakdown voltage of the diodes was found to decrease with temperature     

Formation of Nanocrystalline Calcia by the Decomposition of Calcite

Formation of nanocrystalline calcia from calcite has been studied in situ via transmission electron microscopy. The crystallographic transformation occurred via two mechanisms: the first is by distortion of the cleaved rhombohedron of calcite, formed by {104} planes in hexagonal coordinates, into a cube. This produced a microstructure of oriented, elongated nanocrystals of calcia with planar boundaries. In the second mechanism, the micrometer-sized parent calcite particles broke up into nano-sized grains as the decomposition began, leading to irregularly shaped, randomly oriented nanocrystals of calcia.     

Outage Performance of Uplink (UL) NOMA Network

Wireless Personal Communications - This paper proposes and analyses the power allocation coefficient normalization for successive interference cancellation in power-domain non-orthogonal multiple...     

Dielectric properties of iron doped calcium copper titanate,CaCu<Subscript>3</Subscript>Ti<Subscript>3.9</Subscript>Fe<Subscript>0.1</Subscript>O<Subscript>12</Subscript> ceramic

Dielectric properties of iron doped CaCu₃Ti₄O₁₂ (CCTO), viz. CaCu₃Ti_3.9Fe_0.1O₁₂ (CCTFO) prepared by a novel semi-wet route have been investigated. X-ray diffraction of powder sintered at 900 °C show formation of single phase solid solution. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of CuO rich phase at grain boundaries of CCTFO. Nature of dielectric relaxation observed above room temperature is studied using complex plane impedance analysis and modulus spectroscopy. It has been found that out of the two relaxations reported earlier above room temperature, one occurring at lower temperature is due to grainboundaries interfacial polarization.     

Ytterbium-Doped P$_2$O$_5$-TeO $_2$ Glass for Laser Applications

Ytterbium-doped sodium phospho-tellurite glasses are made with different P₂O₅:TeO₂ ratio, and Yb³⁺ concentrations. Physical properties of the new Yb hosts are favorable for laser applications. The glasses show high absorption and emission cross sections and higher lifetime of Yb³⁺:²F_5/2rarr²F_7/2 transition. The emission cross sections are calculated using two different methods and compared. The laser parameters of these Yb³⁺ -doped glasses are better than many reported glasses and crystals making them potential to fabricate high power laser and broadband optical amplifier in the wavelength region around ~1 mum     

Improved low energy adaptive clustering hierarchy and its optimum cluster head selection

ABSTRACT

Wireless sensor networks (WSNs) play a vital role in present-day world, which are being used in different types of applications and occupy an important part in networking domain. The main objective of WSNs is to sense and collect the information from a given area of interest and provide the gathered data to the sink. WSN comprises of number of sensor nodes with batteries of limited energy for communication and computational activities, which are not possible to recharge the batteries after their deployment in the region of interest. Therefore, saving battery energy and utilising the limited power to the optimum level for extending network lifetime became the main factor of WSN. Hence, optimum cluster head (CH) selection will make the network to support longer lifetime and balanced energy consumption during its lifetime. Our proposed protocol selects the optimum CH and found out to be more efficient than the existing low energy adaptive clustering hierarchy. The simulated output shows better network lifetime and in some other performance metric.     

Multimodal acting in mixed reality interactive storytelling

In this paper, an experimental mixed reality using a multimodal approach is introduced which lets users play characters in interactive narratives as though acting on a stage. Users interact with characters through speech, attitude, and gesture, enhancing their immersion in the virtual world. This system provides a small-scale but complete integration of multimodal communication in interactive storytelling. It uses a narrative's semantic context to focus multimodal input processing-that is, the system interprets users' acting (the multimodal input) in the mixed reality stage in terms of narrative functions representing users' contributions to the unfolding plot.     

Effect of interface states on electron transport in 4H-SiCinversion layers

The effect of trapping in interface states on channel conductance and field-effect mobility in SiC MOSFETs is studied experimentally and theoretically. Hall effect measurements in n-channel MOS devices with varying densities of interface states were used to determine the effect of trapping on carrier mobility. The dependence of electron mobility on immobile interfacial charge density was quantified and was found to be similar to that in silicon, provided that the mobility is normalized to μ₀, the value in the absence of Coulomb scattering. A relationship has been established between the ratio of field-effect mobility to the actual carrier mobility and the density of interface states at the Fermi energy     

Low resistivity as-deposited ohmic contacts to 3C-SiC

The contact resistivities of Al and Ti ohmic contacts to n-type 3C-SiC were measured using the circular TLM method. The surface doping concentration under the contact was increased by ion-implantation of nitrogen into SiC. The contact resistivity was observed to decrease with increasing surface doping concentration for both Al and Ti contacts. The minimum value for the contact resistivities for Aland Ti contacts was 1.4x 10^-5and 1.5 x 10^-5 ω cm², respectively, at the surface doping concentration of 3 x 10²⁰ cm^-3 without any annealing of the contacts. These values are an order of magnitude lower than previously reported minimum values for as-deposited ohmic contacts on n-type 3C-SiC.     

Steganalysis of Network Packet Length Based Data Hiding

Recently, data hiding by modifying network parameters like packet header, payload, and packet length has become popular among researchers. Different algorithms have been proposed during the last few years which have altered the network packets in different ways to embed the data bits. Some of these algorithms modify the network packet length for embedding. Although most of the packet length based embedding schemes try to imitate the normal network traffic distribution, they have altered the statistical distribution of network packet lengths during embedding. These statistical anomalies can be exploited to detect such schemes. In this paper, a second order detection scheme for packet length based steganography has been proposed. A comprehensive set of experiments have been carried out to show that the proposed detection scheme can detect network packet length based steganography with a considerably high accuracy.