| 1. |
- Aidemark, Jan, et al.
(författare)
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A Framework for Strategic Balancing of Knowledge Management Initiatives
- 2003
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Ingår i: Proceedings of the 36th Annual Hawaii International Conference on System Sciences, 2003. - : IEEE Press. - 0769518745
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Konferensbidrag (refereegranskat)abstract
- Enterprises need to understand the impact of different types of knowledge management (KM) approaches on business strategy, and how they interact with other types of initiatives to produce synergistic effects. The hypothesis of this paper is that a model based on the balanced scorecard approach (BSC) can be used to balance the diverse set of KM approaches that are described in the KM literature. A literature study has been carried out connecting general examples of BSC objectives to KM approaches and applications. The resulting framework indicates that each of the major aspects of KM has its place in the BSC model, and thus has a role in the success of the company from a strategic viewpoint. A KM strategy according to this perspective should articulate how a company intends to strike a balance between different KM approaches. Contributions of the framework to related theory are discussed and illustrated by using a rich case from literature.
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| 2. |
- Aidemark, Jan, et al.
(författare)
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An Evaluation of a KM Diagnostic Instrument
- 2007
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Ingår i: Proceedings of the 6th International Conference on Perspectives in Business Information Research - BIR'2007. - Tampere, Finland : Department of Computer Sciences, University of Tampere. - 9789514470967 ; , s. 7-21
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Konferensbidrag (refereegranskat)abstract
- Knowledge management is today an established approach to improve and renew organizations. The right use of information systems are often essential element in a successful KM strategy, however creating the right mix of KM activities and system is difficult and failures are frequent. Getting a good grip of the current situation and the special condition of the organization is therefore essential. In this paper we study an initiating questionnaire, taken from the KM literature, with a background in US management consulting industry. The aim of the paper is to evaluate the questionnaire, from a Swedish perspective. This is done with the aim to search for more general advice for anyone wanting to adapt and use such a questionnaire in their own situation. For this purpose, a number of applications of the questionnaire is presented and investigated. The outcome of the study is an initial assessment of the usefulness of the questionnaire and some recommendations for further use and research into the questionnaire. The usefulness seems to depend on the situation of persons that the questionnaire is given to. The analysis shows that the questionnaire seems to fit rather well to companies that were included in the study, especially on a management level. However, some possible problem areas were also discovered, the background, motivation and work situation of some personnel group could interfere with the effectiveness of the questionnaire.
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| 3. |
- Ala-Laurinaho, J., et al.
(författare)
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TUMESA - MEMS tuneable metamaterials for smart wireless applications
- 2012
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Ingår i: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012. - : IEEE. - 9782874870286 ; , s. 95-98
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Konferensbidrag (refereegranskat)abstract
- This paper describes the main results of the EU FP7 project TUMESA - MEMS tuneable metamaterials for smart wireless applications. In this project, we studied several reconfigurable antenna approaches that combine the new technology of MEMS with the new concept of artificial electromagnetic materials and surfaces (metamaterials and metasurfaces) for realisation of millimetre wave phase shifters and beam-steering devices. MEMS technology allows to miniaturise electronic components, reduce their cost in batch production, and effectively compete with semiconductor and ferroelectric based technologies in terms of losses at millimetre wavelengths. Novel tuneable materials and components proposed in this project perform as smart beam steering devices. Fabricated with MEMS technology in batch and on a single chip, proposed tuneable devices allow substituting of larger and more complex sub-system of, e.g., a radar sensor. This substitution provides a dramatic cost reduction on a system level.
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| 4. |
- Baghchehsaraei, Zargham, 1982-, et al.
(författare)
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Integration of microwave MEMS devices into rectangular waveguide with conductive polymer interposers
- 2013
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 23:12, s. 125020-
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates a novel method of integrating microwave microelectromechanical systems (MEMS) chips into millimeter-wave rectangular waveguides. The fundamental difficulties of merging micromachined with macromachined microwave components, in particular, surface topography, roughness, mechanical stress points and air gaps interrupting the surface currents, are overcome by a double-side adhesive conductive polymer interposer. This interposer provides a uniform electrical contact, stable mechanical connection and a compliant stress distribution interlayer between the MEMS chip and a waveguide frame. The integration method is successfully implemented both for prototype devices of MEMS-tuneable reflective metamaterial surfaces and for MEMS reconfigurable transmissive surfaces. The measured insertion loss of the novel conductive polymer interface is less than 0.4 dB in the E-band (60-90 GHz), as compared to a conventional assembly with an air gap of 2.5 dB loss. Moreover, both dc biasing lines and mechanical feedthroughs to actuators outside the waveguide are demonstrated in this paper, which is achieved by structuring the polymer sheet xurographically. Finite element method simulations were carried out for analyzing the influence of different parameters on the radio frequency performance.
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| 5. |
- Bras, Patrice, et al.
(författare)
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Influence of hydrogen sulfide annealing on copper-zinc-tin-sulfide solar cells sputtered from a quaternary compound target
- 2015
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 582, s. 233-238
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Tidskriftsartikel (refereegranskat)abstract
- With a theoretical efficiency around 30% and an optimized band gap for sunlight absorption, Cu2ZnSnS4 (CZTS) is a promising, earth-abundant, material for thin film solar cells. Sputtering CZTS from a quaternary compound target is a quick and potentially industrial-scaled process that has not been investigated deeply yet. Our approach is based on an in-line vacuum system for the complete device. CZTS is sputtered from a compound target on a sodium molybdate (MoNa) pre-sputtered stainless steel substrate, and then annealed in high-pressure H2S atmosphere. A 1 mu m thick absorber is obtained within 7 minute sputtering. Top layers are then deposited, without vacuum breaking. The effects of different annealing temperatures on the absorber morphology and composition are investigated. It is observed that recrystallization already occurs at 420 degrees C and that crystallinity improves with increasing temperature up to 550 degrees C. However, micro-sphere formation underneath the film degrades the corresponding solar cell performance dramatically above 510 degrees C. It is shown that sodium is needed in order to enhance recrystallization of CZTS but the MoNa layer thickness seems not to be a critical parameter. Scanning electron microscopy, X-ray diffraction, X-ray fluorescence and current-voltage measurement were used to characterize the samples.
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| 6. |
- Bras, Patrice, et al.
(författare)
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Investigation of blister formation in sputtered Cu 2ZnSnS 4 absorbers for thin film solar cells
- 2015
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 33:6
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Tidskriftsartikel (refereegranskat)abstract
- Blister formation in Cu2ZnSnS4 (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials.
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| 7. |
- Bras, Patrice
(författare)
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Sputtering-based processes for thin film chalcogenide solar cells on steel substrates
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Thin film chalcogenide solar cells are promising photovoltaic technologies. Cu(In,Ga)Se2 (CIGS)-based devices are already produced at industrial scale and record laboratory efficiency surpasses 22 %. Cu2ZnSn(S,Se)4 (CZTS) is an alternative material that is based on earth-abundant elements. CZTS device efficiency above 12 % has been obtained, indicating a high potential for improvement.In this thesis, in-line vacuum, sputtering-based processes for the fabrication of complete thin film chalcogenide solar cells on stainless steel substrates are studied. CIGS absorbers are deposited in a one-step high-temperature process using compound targets. CZTS precursors are first deposited by room temperature sputtering and absorbers are then formed by high temperature crystallization in a controlled atmosphere. In both cases, strategies for absorber layer improvement are identified and implemented.The impact of CZTS annealing temperature is studied and it is observed that the absorber grain size increases with annealing temperature up to 550 °C. While performance also improves from 420 to 510 °C, a drop in all solar cell parameters is observed for higher temperature. This loss is caused by blisters forming in the absorber during annealing. Blister formation is found to originate from gas entrapment during precursor sputtering. Increase in substrate temperature or sputtering pressure leads to drastic reduction of gas entrapment and hence alleviate blister formation resulting in improved solar cell parameters, including efficiency.An investigation of bandgap grading in industrial CIGS devices is conducted through one-dimensional simulations and experimental verification. It is found that a single gradient in the conduction band edge extending throughout the absorber combined with a steeper back-grading leads to improved solar cell performance, mainly due to charge carrier collection enhancement.The uniformity of both CIGS and CZTS 6-inch solar cells is assessed. For CZTS, the device uniformity is mainly limited by the in-line annealing process. Uneven heat and gas distribution resulting from natural convection phenomenon leads to significant lateral variation in material properties and device performance. CIGS solar cell uniformity is studied through laterally-resolved material and device characterization combined with SPICE network modeling. The absorber material is found to be laterally homogeneous. Moderate variations observed at the device level are discussed in the context of large area sample characterization.Power conversion efficiency values above 15 % for 225 cm2 CIGS cells and up to 5.1 % for 1 cm2 CZTS solar cells are obtained.
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| 8. |
- Bras, Patrice, et al.
(författare)
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Uniformity assessment of a 6-inch Copper-Zinc-Tin-Sulfide solar cell sputtered from a quaternary compound target
- 2015
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Ingår i: 2015 IEEE 42ND PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC). - 9781479979448
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Konferensbidrag (refereegranskat)abstract
- Cu2ZnSnS4 solar cells are fabricated following an all-sputtering in line vacuum approach. 6-inch semi-square stainless steel substrates are used. A compositional and structural study of the absorber layer is conducted before and after annealing to assess the uniformity of both the sputtering and the annealing process. It is found that while the precursors are uniform both in morphology and composition, the annealing process introduces differences in grain size and metal content depending on the area considered on the 6-inch substrate. The corresponding solar cell is further divided into 184 small cells of 1 cm(2) to check the performance distribution across the device. Current-voltage characteristics and solar cell parameters are extracted. Natural convection inside the annealing chamber is suggested to affect significantly the heat distribution and a strong correlation between device performance and local temperature can be identified.
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