Optical and electrical properties of amorphous zinc tin oxide thin films examined for thin film transistor application

Structural, electronic, and optical properties of amorphous and transparent zinc tin oxide films deposited on glass substrates by pulsed laser deposition (PLD) were examined for two chemical compositions of Zn:Sn=1:1 and 2:1 as a function of oxygen partial pressure PO2 used for the film deposition and annealing temperature. Different from a previous report on sputter-deposited films Chiang et al., Appl. Phys. Lett. 86, 013503 2005 , the PLD-deposited films crystallized at a lower temperature 450 °C to give crystalline ZnO and SnO2 phases. The optical band gaps Tauc gaps were 2.80−2.85 eV and almost independent of oxygen PO2 , which are smaller than those of the corresponding crystals 3.35−3.89 eV . Films deposited at low PO2 showed significant subgap absorptions, which were reduced by postthermal annealing. Hall mobility showed steep increases when carrier concentration exceeded threshold values and the threshold value depended on the film chemical composition. The films deposited at low PO2 2 Pa had low carrier concentrations. It is thought that the low PO2 produced high-density oxygen deficiencies and generated electrons, but these electrons were trapped in localized states, which would be observed as the subgap absorptions. Similar effects were observed for 600 °C crystallized films and their resistivities were increased by formation of subgap states due to the reducing high-temperature condition. High carrier concentrations and large mobilities were obtained in an intermediate PO2 region for the as-deposited films.

Culture and Nutritional Enrichment of the Rotifer Brachionus Rotundiformis ( Tschugunoff ) for the Rearing of Marine Fin Fish and Shrimp Larvae

The present study is an attempt to standardize the environmental condition like pH, salinity and photoperiod, and also the feed for the maximum production of rotifers. Considering the deficiency of essential fatty acids in rotifers, enrichment experiments were carried out and fatty acids profile were analysed. Attempts were made to improve the production of clown fish (Amphiprion sebae) juveniles using enriched rotifers. Attempts were also made to rear various larval stages of Penaeus monodon with enriched rotifers as a substitute for Artemia nauplii.

Toxicity, accumulation and depuration of heavy metalsin the brown mussel perna indica

In this thesis certain important aspects of heavy metal toxicity have been worked out. Recent studies have clearly shown that when experimental media contained more than one heavy metals, such metals could conspicuously influence the toxic reaction of the animals both in terms of quantity and nature. The experimental results available on individual metal toxicity show that, in majority of such results, unrealistically high concentrations of dissolved metals are involved. A remarkable number of factors have been shown to influence metal toxicity such as various environmental factors particularly temperature and salinity, the condition of the organism and the ability of some of the marine organisms to adapt to metallic contamination. Further, some of the more sensitive functions like embryonic and larval development, growth and fecundity, oxygen utilization and the function of various enzymes are found to be demonstrably sensitive in the presence of heavy metals. However, some of the above functions could be compensated for by adaptive process. If it is assumed that the presence of a single metal in higher concentrations could affect the life function of marine animals, more than one metal in the experimental media should manifest such effects in a greater scale. Commonly known as synergism or more than additivity, majority of heavy metals bring about synergistic reaction .The work presented in this thesis comprises lethal and sublethal toxicities of different salt forms of copper and silver on the brown mussel Perna indica. during the present investigation sublethal concentrations of copper and silver in their dent effects on survival, oxygen consumption, filtration, accumulation and depuration on Perna indica. The results are presented under different sections to make the presentation meaningful .

Effect Of Raw Material Quality On The Shelf Life Of Frozen Stored Fish And Fishery Products

Frozen storage characteristics and shelflife vary considerably among species as well as within the species (Powrie, 1973; Fennema. 1973). This can be attributed to the variation in the composition of fish among various species. In certain species like sardines and mackerel. wide seasonal variation in chemical composition occur within the species. These variations affect the quality and shelflife. The nutritional level of water. spawning, method of catching, struggling etc. are found to have profound influence on the condition of the fresh fish. Soon after death the deteriorative changes in fish start due to autolysis and bacterial growth. The rate of these changes depends mainly on temperature. The handling methods have great influence on bacterial contamination. Thus the type oi'handling. temperature control. period of chill storage. processing methods. type of freezing, condition of frozen storage and period of storage affect the quality and shelflife Of the fisho In the present study extensive investigations were carried out on various factors affecting the quality of fish as well as their effect on the physical. chemical and sensory qualities of fish during frozen storage and the shelflife

Studies On Bods And Dissolved Oxygen In The Kadinamkulam Kayal, Southern Kerala

This paper discusses the salient features associated with the variation in the BODs and dissolved oxygen concentration in the Kadinamkulam Kayal based on fortnightly data from two selected stations from October1987toSeptember1988.The BODs ranged from 5.76 to 24.39 mg/l in the surface water and from 4.96 to 22.60mg!1 in the bottom waterat station-l whereas at station-2, it ranged from 0 to 3.74mg/1 in the surface water and from 0 to 3.40 mg!l in the bottom water. The dissolved oxygen concentration ranged from 0 to 0.72 mglI in the surface water and from 0 to 0.42 mg!l in the bottom waterat station-I, At station-2 it ranged from 2.69 to 6.21mg!1 in the surface waterand from 1.97 to 5.74 mg!1 in the bottom water. The pre-monsoom period showed the highest BODsof 16.68mg!I while the monsoon period showed the lowest of 0.61 mg!I. The dissolved oxygen concentration reached its peak during the monsoon period (5.52 mg/I). Long spells of anoxic condition during the post and pre-monsoon periods was a characteristic feature of the retting zone

Length-weight relationship, relative condition factor (Kn) and morphometry of Arius subrostratus (Valenciennes, 1840) from a coastal wetland in Kerala

The length – weight relationship and relative condition factor of the shovel nose catfish, Arius subrostratus (Valenciennes, 1840) from Champakkara backwater were studied by examination of 392 specimens collected during June to September 2008. These fishes ranged from 6 to 29 cm in total length and 5.6 to 218 g in weight. The relation between the total length and weight of Arius subrostratus is described as Log W = -1.530+2.6224 log L for males, Log W = - 2.131 + 3.0914 log L for females and Log W = - 1.742 + 2.8067 log L for sexes combined. The mean relative condition factor (Kn) values ranged from 0.75 to 1.07 for males, 0.944 to 1.407 for females and 0.96 to 1.196 for combined sexes. The length-weight relationship and relative condition factor showed that the well-being of A. subrostratus is good. The morphometric measurements of various body parts and meristic counts were recorded. The morphometric measurements were found to be non-linear and there is no significant difference observed between the two sexes. From the present investigation, the fin formula can be written as D: I, 7; P: I, 12; A: 17 – 20; C: 26 – 32. There is no change in meristic counts with the increase in body length.