The Role of Deep Defect Relaxation Dynamics in Optical Processes in Hydrogenated Amorphous Silicon

1995 ◽  
Vol 377 ◽  
Author(s):  
Fan Zhong ◽  
J. David Cohen

ABSTRACTWe report results of a transient modulated photocurrent technique which allows us to observe the time evolution of the D0 sub-band under the application of optical bias light and after turning off this bias light Our measurements show that the D0 band shifts monotonically to shallower thermal energies after the bias light is applied, with roughly 10 seconds to saturation at 300K and to deeper thermal energies after removing the bias light, with a decay time of over 1000 seconds. We have also found there exists an intimate relation between the motion of the D0 band and that of the quasi Fermi level as deduced from the transient photoconductivity and therefore, in particular, to the long time photoconductivity decay. This relation is exactly reproduced by the assumption of a D0 band whose energy position evolves in time, together with a recombination process dominated by changes in the charge state of a deeper defect band under light bias.

1986 ◽  
Vol 69 ◽  
Author(s):  
M. Kunst ◽  
A. Werner

AbstractTransient photoconductivity measurements with the time-resolved microwave conductivity (TRMC) method have been applied to three different types of semiconductors: hydrogenated amorphous silicon, single crystalline silicon and GaAs/GaAlAs multiple quantum well structures. Analysis of the signals in terms of charge carrier-lattice interaction points to an intimate relation between TRMC signals and intrinsic material properties. It is shown that the TRMC-technique is an excellent tool to characterize photosensitive materials.


1993 ◽  
Vol 297 ◽  
Author(s):  
D. Caputo ◽  
G. De Cesare ◽  
G. Irrera ◽  
G. Masini ◽  
F. Palma ◽  
...  

Photoconductivity decay during monochromatic illumination has been measured on an ensemble of a-Si:H films deposited at different substrate temperatures. Degradation behaviour has been modelled within the framework of the bond-breaking model (dN/dt = Csw np). Simmons and Taylor recombination kinetics has been assumed, taking into account the divalent nature of dangling bonds and their three possible conditions of occupancy. The Staebler-Wronski susceptibility (Csw) has been extracted through a fitting procedure. As a result, a correlation between the obtained Csw and the measured electronic, optical and structural properties of as deposited a-Si:H films can be inferred.


1994 ◽  
Vol 336 ◽  
Author(s):  
Adam Gardner ◽  
J. David Cohen

ABSTRACTWe have carried out a series of charge transient measurements on a-Si:H in which we insert a double temperature step during the period when electrons are being emitted from deep defects. The behavior of this emitted defect charge is completely inconsistent with any density of states that remains static during the emission; that is, defect relaxation must be invoked. Such measurements allow us to separate the temperature dependence of relaxation from that of thermal emission. In particular, we demonstrate that the emission itself exhibits thermally activated behavior in spite of the ongoing relaxation processes.


2008 ◽  
pp. 61-76
Author(s):  
A. Porshakov ◽  
A. Ponomarenko

The role of monetary factor in generating inflationary processes in Russia has stimulated various debates in social and scientific circles for a relatively long time. The authors show that identification of the specificity of relationship between money and inflation requires a complex approach based on statistical modeling and involving a wide range of indicators relevant for the price changes in the economy. As a result a model of inflation for Russia implying the decomposition of inflation dynamics into demand-side and supply-side factors is suggested. The main conclusion drawn is that during the recent years the volume of inflationary pressures in the Russian economy has been determined by the deviation of money supply from money demand, rather than by money supply alone. At the same time, monetary factor has a long-run spread over time impact on inflation.


Author(s):  
М. В. Дзисюк

Definitions of concept and sphere of the concept are widely used in different aspects of modern linguistics. There is no single understanding of these notions and universal methodology of research has not been invented by linguists yet. This predetermines topicality of the article. The aim of our research is analysis, generalization, and systematization of different approaches to the interpretation of the notion ‘concept’ that exist in modern linguistics. It results in the following tasks: analysis of existing definitions of concept and its division into certain ranges and defining classification features. Modern linguists raise the questions of the conceptual and linguistic image of the world, the role of a human factor in its formation and interaction as in a linguistic process more frequently and it is defined as a fact in today’s linguistic scientific literature. The problem of individual language formation, poetic one in particular gains important meaning in this context. Ukrainian linguists use the notion of ‘concept’ for a long time now although they adhere to different views on its definition. Researches of the question define two major approaches in the analysis of the notion ‘concept’ that is linguistic-cognitive and linguistic-cultural. We can claim that words-concepts are agents between material reality and the ideal world that is synthesized in poetry, carriers of sense since with their help the versatility of the real world correlates with eternal spiritual values. Therefore, main features of the notion ‘concept’ in which objectively-cognitive and subjectively-creative features are combines are as follow sensual authenticity, time-spatial features, mediation between material and spiritual, semantic filling, ability to polysemy. A word with a generally symbolic meaning that is implemented in a language process through literary techniques typical for poet’s idiotype is the main core of the concept. The concept in poetic language formation by modern Uman poets is semantically integral, fulfilled, able to penetrate into other concepts and absorb semantically narrower images saving unity and semantic independence, varying numerous interpretations that project it in a certain semantic space, saving potential of real reflection.


Author(s):  
Madara Eversone

The article aims to highlight the role of Arvīds Grigulis’ (1906–1989) personality in the Latvian Soviet literary process in the context of the Latvian Soviet Writers’ Union, attempting to discover the contradictions and significance of Arvīds Grigulis’ personality. Arvīds Grigulis was a long-time member of the Writers’ Union, a member of the Soviet nomenklatura, and an authority of the soviet literary process. His evaluations of pre-soviet literary heritage and writings of his contemporaries were often harsh and ruthless, and also influenced the development of the further literary process. The article is based on the documents of the Central Committee of the Latvian Communist Party, the Latvian Soviet Writers’ Union and the Communist Party local organization of the Latvian Soviet Writers’ Union that are available at the Latvian State Archive of the National Archives of Latvia, as well as memories of Grigulis’ contemporaries. It is concluded that the personality of the writer Arvīds Grigulis, although unfolding less in the context of the Writers’ Union, is essential for the exploration of the soviet literary process and events behind the scenes. The article mainly describes events and episodes taking place until 1965, when Arvīds Grigulis’ influence in the Writers’ Union was more remarkable. Individual and further studies should analyse changes and the impact of his decisions in the cultural process of the 70s and 80s of the 20th century.


Author(s):  
Stefan Gründer

Acid-sensing ion channels (ASICs) are proton-gated Na+ channels. Being almost ubiquitously present in neurons of the vertebrate nervous system, their precise function remained obscure for a long time. Various animal toxins that bind to ASICs with high affinity and specificity have been tremendously helpful in uncovering the role of ASICs. We now know that they contribute to synaptic transmission at excitatory synapses as well as to sensing metabolic acidosis and nociception. Moreover, detailed characterization of mouse models uncovered an unanticipated role of ASICs in disorders of the nervous system like stroke, multiple sclerosis, and pathological pain. This review provides an overview on the expression, structure, and pharmacology of ASICs plus a summary of what is known and what is still unknown about their physiological functions and their roles in diseases.


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