scispace - formally typeset
Search or ask a question
Institution

Linköping University

EducationLinköping, Sweden
About: Linköping University is a education organization based out in Linköping, Sweden. It is known for research contribution in the topics: Population & Thin film. The organization has 15671 authors who have published 50013 publications receiving 1542189 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a single crystalline and highly resistive wurtzite ZnO films were obtained from infrared (300-1200 cm−1) spectroscopic ellipsometry and Raman scattering studies.
Abstract: Infrared dielectric function spectra and phonon modes of high-quality, single crystalline, and highly resistive wurtzite ZnO films were obtained from infrared (300–1200 cm−1) spectroscopic ellipsometry and Raman scattering studies. The ZnO films were deposited by pulsed-laser deposition on c-plane sapphire substrates and investigated by high-resolution x-ray diffraction, high-resolution transmission electron microscopy, and Rutherford backscattering experiments. The crystal structure, phonon modes, and dielectric functions are compared to those obtained from a single-crystal ZnO bulk sample. The film ZnO phonon mode frequencies are highly consistent with those of the bulk material. A small redshift of the longitudinal optical phonon mode frequencies of the ZnO films with respect to the bulk material is observed. This is tentatively assigned to the existence of vacancy point defects within the films. Accurate long-wavelength dielectric constant limits of ZnO are obtained from the infrared ellipsometry anal...

580 citations

Journal ArticleDOI
TL;DR: In this article, the authors argue that too much effort has been dedicated to clarifying the reasons of project success and failure, while downplaying a number of important research questions that need to be discussed in order to further the knowledge about project management.

579 citations

Journal ArticleDOI
23 Jun 1995-Science
TL;DR: This method, which avoids the use of a sacrificial layer and allows the actuators to pull themselves off the surface, may have general applications in micromachining, including the manufacture, of surfaces whose light reflection or chemical properties can be switched.
Abstract: Several types of microactuators have been fabricated, from simple paddles to self-assembling and -disassembling cubes. Conducting bilayers made of a layer of polymer and a layer of gold were used as hinges to connect rigid plates to each other and to a silicon substrate. The bending of the hinges was electrically controlled and reversible, allowing precise three-dimensional positioning of the plates. The structures were released from the substrate with a technique based on differential adhesion. This method, which avoids the use of a sacrificial layer and allows the actuators to pull themselves off the surface, may have general applications in micromachining. Possibilities include the manufacture, of surfaces whose light reflection or chemical properties can be switched.

579 citations

Journal ArticleDOI
TL;DR: A low-complexity algorithm is proposed to obtain the stationary solution for the joint design problem by utilizing the fractional programming technique and extended to the scenario wherein the CSI is imperfect.
Abstract: Reconfigurable intelligent surfaces (RIS) is a promising solution to build a programmable wireless environment via steering the incident signal in fully customizable ways with reconfigurable passive elements. In this paper, we consider a RIS-aided multiuser multiple-input single-output (MISO) downlink communication system. Our objective is to maximize the weighted sum-rate (WSR) of all users by joint designing the beamforming at the access point (AP) and the phase vector of the RIS elements, while both the perfect channel state information (CSI) setup and the imperfect CSI setup are investigated. For perfect CSI setup, a low-complexity algorithm is proposed to obtain the stationary solution for the joint design problem by utilizing the fractional programming technique. Then, we resort to the stochastic successive convex approximation technique and extend the proposed algorithm to the scenario wherein the CSI is imperfect. The validity of the proposed methods is confirmed by numerical results. In particular, the proposed algorithm performs quite well when the channel uncertainty is smaller than 10%.

576 citations

Journal ArticleDOI
TL;DR: Surprisingly, it is found that C 1s shifts correlate to changes in sample work function ϕSA, such that the sum EBF+ϕSA is constant at 289.50±0.15 eV, irrespective of materials system and air exposure time, indicating vacuum level alignment.
Abstract: The C 1s signal from ubiquitous carbon contamination on samples forming during air exposure, so called adventitious carbon (AdC) layers, is the most common binding energy (BE) reference in X-ray photoelectron spectroscopy studies. We demonstrate here, by using a series of transition-metal nitride films with different AdC coverage, that the BE of the C 1s peak EBF varies by as much as 1.44 eV. This is a factor of 10 more than the typical resolvable difference between two chemical states of the same element, which makes BE referencing against the C 1s peak highly unreliable. Surprisingly, we find that C 1s shifts correlate to changes in sample work function ϕSA , such that the sum EBF+ϕSA is constant at 289.50±0.15 eV, irrespective of materials system and air exposure time, indicating vacuum level alignment. This discovery allows for significantly better accuracy of chemical state determination than offered by the conventional methods. Our findings are not specific to nitrides and likely apply to all systems in which charge transfer at the AdC/substrate interface is negligible.

575 citations


Authors

Showing all 15844 results

NameH-indexPapersCitations
Rui Zhang1512625107917
Jun Lu135152699767
Jean-Luc Brédas134102685803
Lars Wallentin12476761020
S. Shankar Sastry12285886155
Gerhard Andersson11890249159
Olle Inganäs11362750562
Antonio Facchetti11160251885
Ray H. Baughman11061660009
Michel W. Barsoum10654360539
Louis J. Ignarro10633546008
Per Björntorp10538640321
Jan Lubinski10368952120
Magnus Johannesson10234240776
Barbara Riegel10150777674
Network Information
Related Institutions (5)
Lund University
124.6K papers, 5M citations

96% related

Katholieke Universiteit Leuven
176.5K papers, 6.2M citations

94% related

National University of Singapore
165.4K papers, 5.4M citations

93% related

University of Copenhagen
149.7K papers, 5.9M citations

93% related

University of Southern California
169.9K papers, 7.8M citations

93% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
202385
2022359
20213,190
20203,210
20193,029