Thermal annealing behaviour on electrical properties of Pd/Ru Schottky contacts on n-type GaN

We have investigated the electrical properties of Pd/Ru Schottky contacts on n-GaN as a function of annealing temperature by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The Schottky barrier height of the as-deposited Pd/Ru contact is found to be 0.67 eV (I-V) and 0.79 eV (C-V), respectively. Measurements showed that the Schottky barrier height increased from 0.68 eV (I-V) and 0.80 eV (C-V) to 0.80 eV (I-V) and 0.96 eV (C-V) as the annealing temperature is varied from 200 °C to 300 °C. Upon annealing at 400 °C and 500 °C, the Schottky barrier height decreased to 0.73 eV (I-V) and 0.85 eV (C-V) and 0.72 eV (I-V) and 0.84 eV (C-V), respectively. It is noted that the barrier height further decreased to 0.59 eV (I-V) and 0.72 eV (C-V) when the contact is annealed at 600 °C. The change of Schottky barrier heights and ideality factors with annealing temperature may be due to the formation of interfacial compounds at the Ru/Pd/n-GaN interface. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2788

Battery energy storage based voltage and frequency controller for isolated pico hydro systems

This paper deals with an integrated voltage and frequency (VF) controller for isolated asynchronous generators (IAG) driven by a constant power pico-hydro uncontrolled turbine feeding three-phase four-wire loads. The proposed VF controller is used to control the frequency and voltage of an IAG with load leveling. Such a VF controller is also known as an integrated electronic load controller (IELC) which is realized using an isolated star/polygon transformer with a voltage source converter (VSC) and a battery at its DC bus. The proposed generating system with a VFC is modeled and simulated in MATLAB along with Simulink and Simpower system (SPS) toolboxes. The simulated results are presented to demonstrate the performance of an isolated asynchronous generator feeding three-phase four-wire loads with neutral current compensation

Electrical Transport Characteristics and Deep Level Transient Spectroscopy of Ni/V/n-InP Schottky Barrier Diodes

We report on the temperature-dependent electrical characteristics and deep level transient spectroscopy (DLTS) of the Ni/V/n-InP Schottky diodes in the temperature range of 180-420 K. Current density - voltage (J-V) characteristics of these diodes have been analyzed on the basis of thermionic emission theory with Gaussian distribution model of barrier height. The calculated Schottky barrier height (bo) and ideality factor (n) of Ni/V Schottky contact is in the range of 0.39 eV and 2.36 at 180 K, and 0.69 eV and 1.27 at 420 K, respectively. It is observed that the zero-bias barrier height increases while ideality factor decreases with increasing temperature. A bo versus q/2kT plot is drawn to obtain evidence of a Gaussian distribution of the barrier heights, and values of = 0.95 eV and 0 = 128 eV for the mean barrier height and standard deviation. A modified Richardson plot gives (T=0)= 0.98 eV and Richardson constant (A*) = 7.068 A K – 2cm – 2. The discrepancy between Schottky barrier height (SBHs) estimated from J-V and C-V measurements is also discussed. Thus, it is concluded that the temperature dependence of J-V characteristics of the SBHs on n-InP can be explained on the basis of themionic emission mechanism with Gaussian distribution of the barrier heights. DLTS results showed that two deep levels are identified (E1 and E2) in as-grown sample having activation energies of 0.29 ± 0.01 and 0.69 ± 0.02 with capture cross-section 3.29 × 10 – 15 cm2 and 5.85 × 10 – 17 cm2 respectively. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2777

Contribution to the knowledge of ornamental molluscs of Parangipettai, Southeast Coast of India

The ornamental shell industry in India in recent years is a multimillion dollar industry. India’s ornamental trade is currently worth US$ 278 million. The collection of molluscan shells is a popular activity in coastal areas. Ornamental molluscs are sold in the market exclusively for aquarium and ornamental purposes. Molluscan shells are used in studs like ear-rings, bangles, table lamps, spoons cups and saucers etc., and it is also used in Aquarium. A study was carried out on ornamental molluscan resources of Tamil nadu coast to identify, quantify and assess the shell resources potential for development of a small-scale shell industry and also a suitable collection techniques and methods of shell catalogue preparation during Oct 2007 to Sep 2008. Gastropods and bivalves have been collected for ornamental purpose by the fisher folks. During the survey gastropods and bivalve species belonging to 21families such as Turritellidae, Cypraeidae, Volutidae, Muricidae, Conidae, Trochidae, Olividae, Cassidae, Marginellidae, Bursidae, Strombidae, Buccinidae, Naticidae, Tonnidae, Melongenidae, Vassidae, Harpidae, Architectonidae Arcidae, Pectinidae, Veneridae, were collected. From the total molluscan diversity 85% were exclusively ornamental molluscs. The study revealed that the occurrence of gastropods and bivalves species here are most valuable shells and naturally rare and not easily available

Electrical transport characteristics of Pd/V/N-InP Schottky diode from I-V-T and C-V-T measurements

The temperature dependence of current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Pd/V contacts on undoped n-type InP Schottky barrier diodes (SBDs) have been systematically investigated in the temperature range of 200-400 K. The transition metal palladium (Pd) is used as a second contact layer because it has high work function, it reacts with InP at low temperatures and improved contact morphology. The ideality factor (n) and zero-bias barrier height are found to be strongly temperature dependent and while the zero-bias barrier height Φbo (I-V) increases, the ideality factor n decreases with increasing temperature. The experimental values of BH and n for the devices are calculated as 0.48 eV (I-V), 0.85 eV (C-V) and 4.87 at 200 K, 0.65 eV (I-V), 0.69 (C-V) eV and 1.58 at 400 K respectively. The I-V characteristics are analyzed on the basis of thermionic emission (TE) theory and the assumption of Gaussian distribution of barrier heights due to barrier inhomogeneities that prevail at the metal-semiconductor interface. The zero-bias barrier height Φbo versus 1/2kT plot has been drawn to obtain the evidence of a Gaussian distribution of the heights and the values of φ=0.89 eV and σ0= 145 meV for the mean barrier height and standard deviation. The conventional Richardson plot exhibits non-linearity with activation energy of 0.53 eV and the Richardson constant value of 4.25 × 10– 6 Acm– 2 K– 2. From the C-V characteristics, measured at 1 MHz the capacitance was determined to increase with increasing temperature. C-V measurements have resulted in higher barrier heights than those obtained from I-V measurements. As a result, it can be concluded that the temperature dependent characteristic parameters for Pd/V/n-InP SBDs can be successfully explained on the basis of TE mechanism with Gaussian distribution of the barrier heights. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

Biochemical composition of different body parts of Gafrarium tumidum (Roding, 1798) from Mandapam, South East Coast of India

Due to its abundance in various areas along the Mandapam coast (latitude 9° 17”N; longitude 79° 11”E), Southeast coast of India, the commonly occurring intertidal bivalve Gafrarium tumidum was selected for this study to investigate its nutritive value. Tissues of different body parts such as mantle, viscera and foot were analyzed. Biochemical constituents like protein, carbohydrate and fat were estimated in different body parts and the percentage of protein was 61.74%, carbohydrate 32.64% and lipid 14.37%. The fatty acids of bivalve were analyzed by gas chromatography/mass spectrometry. In the fatty acids, polyunsaturated fatty acids (PUFA) were found to be dominant, contributing 6.99% (2.34, 2.67 and 1.98% mantle, viscera and foot, respectively), whereas saturated fatty acids (SFA) contributed 5.19% (1.70, 1.94 and 1.55%) followed by monounsaturated fatty acids (MUFA) which contributed 2.75% (0.92 0.93 0.90%). Stearic (0.81%) and palmitic acids (0.71%) were the dominant saturated fatty acid in viscera and oleic acid (0.93%) was the monounsaturated fatty acid found in the viscera. Linoleic (1.38%) and α- linolenic acids (1.07%) were the dominant polyunsaturated fatty acid in viscera. The total amino acid detected was found to be 42.97%, among them the essential amino acids (EAA) was 20.77% and the non essential amino acids (NEAA) present was found to be 22.2%. The results of this study revealed that phenylalanine (1.19%) and methionine (1.04%) in EAA and alanine (1.10%) and glutamic acid (1.10%) in NEAA were the major constituents. It could also be added that the composition of marine bivalves is a nutritional assurance to millions of malnourished people