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We have employed technology computer-aided design – a Synopsys® tool to carry out a comparative study of the electrical behaviour of the metal–insulator–semiconductor Schottky diodes with different metal contacts (Ag, Au, Pt and Cr), on n-Si(100). We employed physics models to determine the Shockley–Read–Hall (SRH) and Auger recombination rates as a function of electric field profile in the depletion region. An insight was obtained as variation in the electric field at the metal–semiconductor interface due to work function variation affected the current mechanisms and recombination rates. The results were compared with the existing models. On the basis of analysis, merits and demerits of Schottky junctions formed due to these metals are discussed. The ideality factor of Au and Pt was found to be just around 2.0, while it was higher for Cr and Ag. However, the barrier height in the case of Cr was small, thus making it another possible metal layer for the Schottky contact. Similarly, SRH recombination rates were almost negligible for Au and Pt metal layer and became appreciable for Cr and much higher in Ag, making it not a good choice for the Schottky contact. [ABSTRACT FROM PUBLISHER]

In recent years, methylenedioxymethamphetamine (MDMA or ecstasy) has gained great popularity among young adults. Although human research in abstinent users has focused primarily on memory function, little attention has been given to other neuropsychological functions that may have some bearing on memory performance, such as attention. Hence, the purpose of this study was to examine the effects of MDMA on attentional processes. Accordingly, 24 MDMA users and 30 matched normal controls were tested on the Wechsler Abbreviated Scale of Intelligence (WASI) and the Test of Everyday Attention (TEA). We found MDMA users to show generally no significant difference on attention tasks compared with controls with the exception of a single TEA subtest. More interestingly, we found some preliminary evidence to indicate that dosage, in terms of the number of tablets used, may be related to impairment on specific component attentional tasks. This finding brings to light the important relationship between poor attentional processes and drug-taking behaviors and their reciprocal relationship. [ABSTRACT FROM AUTHOR]