Trap - deep

Figure 7.5 Schematic presentation of photoactivation and relaxation processes in a CdSe quantum dot aggregate (a) surface-passivation of photoexcited quantum dots by solvent molecules or dissolved oxygen, (b) thermal activation followed by the formation ofa stabilized state, (c) the formation of deep-trap states, (d) non-radiative relaxation of deep-...

Fig. 4 Schematic representation of long-distance radical cation migration in DNA. In AQ-DNA(l), irradiation of the anthraquinone group linked at the 5 -terminus leads to reaction at GG steps that are 27 A and 44 A from the site of charge injection. The amount of reaction observed at each guanine is represented approximately by the length of the solid arrow. In UAQ-DNA(2), irradiation of the anthraquinone leads to reaction at each of the eight GG steps. However, replacement of a G by 7,8-dihydro-8-oxoguanine (8-OxoG) introduces a deep trap that inhibits reaction at guanines on the same side of the DNA as the trap...

Various mechanisms for electret effect formation in anodic oxides have been proposed. Lobushkin and co-workers241,242 assumed that it is caused by electrons captured at deep trap levels in oxides. This point of view was supported by Zudov and Zudova.244,250 Mikho and Koleboshin272 postulated that the surface charge of anodic oxides is caused by dissociation of water molecules at the oxide-electrolyte interface and absorption of OH groups. This mechanism was put forward to explain the restoration of the electret effect by UV irradiation of depolarized samples. Parkhutik and Shershulskii62 assumed that the electret effect is caused by the accumulation of incorporated anions into the growing oxide. They based their conclusions on measurements of the kinetics of Us accumulation in anodic oxides and comparative analyses of the kinetics of chemical composition variation of growing oxides. 

Figure 43 illustrates the possible current transients during thermal treatment of Al-anodic Al203-Au structures at linearly increasing temperature (a) and during isothermal annealing (b). The first case is characterized by a TSC maximum at —400 K followed by a change in current direction and a second maximum (Fig. 43a). In the case of isothermal treatment, jTSC follows a t n dependence, where n is close to unity. These findings are usually interpreted in terms of a release from deep traps of those electrons that were initially captured there in the process of anodization. There are no clear ideas as to the physical nature of these traps. Parkhutik and Shershulskii249 have postulated that traps are associ-...

A group of scientists have studied current transients in biased M-O-M structures.271,300 The general behavior of such a system may be described by classic theoretical work.268,302 However, the specific behavior of current transients in anodic oxides made it necessary to develop a special model for nonsteady current flow applicable to this case. Aris and Lewis have put forward an assumption that current transients in anodic oxides are due to carrier trapping and release in the two systems of localized states (shallow and deep traps) associated with oxygen vacancies and/or incorporated impurities.301 This approach was further supported by others,271,279 and it generally resembles the oxide band structure theoretically modeled by Parkhutik and Shershulskii62 (see. Fig. 37). 

Laboratory rooms intended for toxic work should be provided with adjacent shower and change facilities. The layout must not require freshly showered personnel to track back through the area that they might have just contaminated. All drains, including those in laboratory floors, should have deep traps and be directed to a toxic sump. Airlocks will help prevent toxic fumes from spreading to non-toxic areas in the event of a failure of a primary containment cabinet. Check valves in the incoming water lines will prevent contamination of potable water supplies when pressure is lost. 

H Antoniadis, MA Abkowitz, and BR Hsieh, Carrier deep-trapping mobility — lifetime products in poly(p-phenylene vinylene), Appl. Phys. Lett., 65 2030-2032, 1994. 

I5A. J. Kumnick, and H. H. Johnson, Deep Trapping States for Hydrogen in Deformed Iron, Acta Metall., 28(1), 33-39 (1980). 

Ti02 with some functional groups such as carboxylic and thiol or amino, which, through chelation, modify the electrochemical properties of the metal ions and/or introduce deep trapping sites physically separated from the oxide and allowing improved electron-hole charge separation. ... 

Arkhipov VI, Heremans P, Emelianova EV, Adriaenssens GJ, Bassler H (2002) Weak-field carrier hopping in disordered organic semiconductors the effects of deep traps and partly filled density-of-states distribution. J Phys Condens Matter 14 9899... 

Sevilla et al. have shown that HO is not detected in relatively dry DNA (F < 8), but is detected in the F > 8 waters per nucleotide, suggesting that all holes do not transfer to DNA in the regime (8 > F > 22). The sites where these holes are initially produced are not particularly good hole traps. The holes move about until they encounter deep traps such as guanine. 

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