The effect of different mild post-annealing treatments in air, at 270 degrees C, for 4-6 min, on the optical, electrical, structural and chemical properties of copper sulphide (CuxS) thin films deposited at room temperature are investigated. CuxS films, 70nm thick, are deposited on glass substrates by vacuum thermal evaporation from a Cu2S:S (50:50 wt.%) sulphur rich powder mixture. The as-deposited highly conductive crystalline CuS (covellite) films show high carrier concentration (similar to 10(22) cm(-3)), low electrical resistivity (similar to 10(-4) Omega cm) and inconclusive p-type conduction. After the mild post-annealing, these films display increasing values of resistivity (similar to 10(-3) to similar to 10(-2) Omega cm) with annealing time and exhibit conclusive p-type conduction. An increase of copper content in CuxS phases towards the semiconductive Cu2S (chalcocite) compound with annealing time is reported, due to re-evaporation of sulphur from the films. However, the latter stoichiometry was not obtained, which indicates the presence of vacancies in the Cu lattice. In the most resistive films a Cu2O phase is also observed, diminishing the amount of available copper to combine with sulphur, and therefore the highest values of optical transmittance are reached (65%). The appearance on the surface of amorphous sulphates with annealing time increase is also detected as a consequence of sulphur oxidation and replacement of sulphur with oxygen. All annealed films are copper deficient in regards to the stoichiometric Cu2S and exhibit stable p-type conductivity. (C) 2011 Elsevier B.V. All rights reserved.

The effect of different mild post-annealing treatments in air, at 270 degrees C, for 4-6 min, on the optical, electrical, structural and chemical properties of copper sulphide (CuxS) thin films deposited at room temperature are investigated. CuxS films, 70nm thick, are deposited on glass substrates by vacuum thermal evaporation from a Cu2S:S (50:50 wt.%) sulphur rich powder mixture. The as-deposited highly conductive crystalline CuS (covellite) films show high carrier concentration (similar to 10(22) cm(-3)), low electrical resistivity (similar to 10(-4) Omega cm) and inconclusive p-type conduction. After the mild post-annealing, these films display increasing values of resistivity (similar to 10(-3) to similar to 10(-2) Omega cm) with annealing time and exhibit conclusive p-type conduction. An increase of copper content in CuxS phases towards the semiconductive Cu2S (chalcocite) compound with annealing time is reported, due to re-evaporation of sulphur from the films. However, the latter stoichiometry was not obtained, which indicates the presence of vacancies in the Cu lattice. In the most resistive films a Cu2O phase is also observed, diminishing the amount of available copper to combine with sulphur, and therefore the highest values of optical transmittance are reached (65%). The appearance on the surface of amorphous sulphates with annealing time increase is also detected as a consequence of sulphur oxidation and replacement of sulphur with oxygen. All annealed films are copper deficient in regards to the stoichiometric Cu2S and exhibit stable p-type conductivity. (C) 2011 Elsevier B.V. All rights reserved.

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Domain Specic Languages (DSLs) are claimed to contribute
to increment productivity, while reducing the required maintenance and
programming expertise. In this context, the usability of these languages
becomes a major issue: if the language is not easy to learn and use, it is
unlikely to be successfully adopted.

It is important to foster high quality DSLs during its engineering process.
We argue that a systematic approach based on User Interface Experi-
mental validation techniques should be used to assess the impact of the
introduction of DSLs in the productivity of DSL user. Productivity can
be fostered by assessing important usability attributes early in the lan-
guage construction . This work's contribution, besides highlighting the
problem of the absence of systematic approaches for experimental vali-
dation of DSLs in general, is to identify existing evaluation approaches
that can be adapted from the eld of User Interfaces.

KAOS is one of the most well-known goal-oriented requirements engineering approaches. Nevertheless, building large KAOS models sometimes results in incomplete and/or complex requirements models that are difficult to understand and maintain. These shortcomings often lead to an increase in costs of product development and evolution. Therefore, for large-scale systems, the ability to manage the complexity and completeness of KAOS models is essential. In this paper, we propose a metrics suite for supporting the quantitative assessment of KAOS models complexity and completeness, in order to support their early identification. We apply the metrics to an example taken from a health club system specification.

Scenario modeling can be realized through different perspectives. In UML, scenarios are often modeled with activity models, in an early stage of development. Later, sequence diagrams are used to detail object interactions. The migration from activity diagrams to sequence diagrams is a repetitive and error-prone task. Model-Driven Development (MDD) can help streamlining this process, through transformation rules. Since the information in the activity model is insufficient to generate the corresponding complete sequence model, manual refinements are required. Our goal is to compare the relative effort of building the sequence diagrams manually with that of building them semi-automatically. Our results show a decrease in the number of operations required to build and refine the sequence model of approximately 64% when using MDD, when compared to the manual approach.