| 1. |
- Delmas, Marie, et al.
(författare)
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High performance type-II InAs/GaSb superlattice infrared photodetectors with a short cut-off wavelength
- 2023
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Ingår i: Opto-Electronics Review. - : Polish Academy of Sciences Chancellery. - 1230-3402 .- 1896-3757. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the potential of InAs/GaSb superlattice detectors for the short -wavelength infrared spectral band. A barrier detector structure was grown by molecular beam epitaxy and devices were fabricated using standard photolithography techniques. Optical and electrical characterisations were carried out and the current limitations were identified. The authors found that the short diffusion length of similar to 1.8 mu m is currently limiting the quantum efficiency (double-pass, no anti-reflection coating) to 43% at 2.8 mu m and 200 K. The dark current density is limited by the surface leakage current which shows generation-recombination and diffusion characters below and above 195 K, respectively. By fitting the size dependence of the dark current, the bulk values have been estimated to be 6.57 center dot 10(-6)A/cm(2) at 200 K and 2.31 center dot 10(-6) A/cm(2) at 250 K, which is only a factor of 4 and 2, respectively, above the Rule07.
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| 2. |
- Hamm, Michael, et al.
(författare)
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BRN2 is a non-canonical melanoma tumor-suppressor
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- While the major drivers of melanoma initiation, including activation of NRAS/BRAF and loss of PTEN or CDKN2A, have been identified, the role of key transcription factors that impose altered transcriptional states in response to deregulated signaling is not well understood. The POU domain transcription factor BRN2 is a key regulator of melanoma invasion, yet its role in melanoma initiation remains unknown. Here, in a BrafV600EPtenF/+ context, we show that BRN2 haplo-insufficiency promotes melanoma initiation and metastasis. However, metastatic colonization is less efficient in the absence of Brn2. Mechanistically, BRN2 directly induces PTEN expression and in consequence represses PI3K signaling. Moreover, MITF, a BRN2 target, represses PTEN transcription. Collectively, our results suggest that on a PTEN heterozygous background somatic deletion of one BRN2 allele and temporal regulation of the other allele elicits melanoma initiation and progression.
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| 3. |
- Ivanov, Ruslan, et al.
(författare)
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T2SL development for space at IRnova : from eSWIR to VLWIR
- 2019
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Ingår i: Sensors, Systems, and Next-Generation Satellites XXIII. - : SPIE - International Society for Optical Engineering. - 9781510630062
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Konferensbidrag (refereegranskat)abstract
- In this paper, results from the development of InAs/GaSb superlattice focal plane arrays (FPAs) at IRnova will be presented. A versatile and robust detector design is used that allows for adjustment of the detection cut-off wavelength from 2.5 mu m up to 14.5 mu m with only minor changes in the detector design. Performance of the fabricated detectors has been reviewed in terms of external quantum efficiency (EQE), dark current and noise for three designs with cut-off wavelengths of 4, 5.5 and 11 mu m at 80 K (referred to as DEEP BLUE, RED HOT and VLWIR, respectively). Measurements on the 15 mu m sized photodiodes demonstrated 70 % EQE for the MWIR designs, and almost 40 % for VLWIR. At the same time, the dark current stayed close to the Rule07 benchmark for all studied samples. Noise mechanisms have been discussed and their relation to the passivation was examined. Mature in-house processing and passivation technique resulted in very high spatial uniformity of VGA focal plane arrays (FPAs), i.e. low relative deviations of EQE (< 6 %) and of dark current density (< 12 %), and narrow noise distributions for both RED HOT and DEEP BLUE FPAs. We show also that >99.5 % of these arrays operate close to the fundamental noise limit.
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| 4. |
- Luquiens, Amandine, et al.
(författare)
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Pictograms to aid laypeople in identifying the addictiveness of gambling products (PictoGRRed study)
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The structural addictive characteristics of gambling products are important targets for prevention, but can be unintuitive to laypeople. In the PictoGRRed (Pictograms for Gambling Risk Reduction) study, we aimed to develop pictograms that illustrate the main addictive characteristics of gambling products and to assess their impact on identifying the addictiveness of gambling products by laypeople. We conducted a three-step study: (1) use of a Delphi consensus method among 56 experts from 13 countries to reach a consensus on the 10 structural addictive characteristics of gambling products to be illustrated by pictograms and their associated definitions, (2) development of 10 pictograms and their definitions, and (3) study in the general population to assess the impact of exposure to the pictograms and their definitions (n = 900). French-speaking experts from the panel assessed the addictiveness of gambling products (n = 25), in which the mean of expert’s ratings was considered as the true value. Participants were randomly provided with the pictograms and their definitions, or with a standard slogan, or with neither (control group). We considered the control group as representing the baseline ability of laypeople to assess the addictiveness of gambling products. Each group and the French-speaking experts rated the addictiveness of 14 gambling products. The judgment criterion was the intraclass coefficients (ICCs) between the mean ratings of each group and the experts, reflecting the level of agreement between each group and the experts. Exposure to the pictograms and their definition doubled the ability of laypeople to assess the addictiveness of gambling products compared with that of the group that read a slogan or the control group (ICC = 0.28 vs. 0.14 (Slogan) and 0.14 (Control)). Laypeople have limited awareness of the addictive characteristics of gambling products. The pictograms developed herein represent an innovative tool for universally empowering prevention and for selective prevention.
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| 5. |
- Ramos Santesmases, David, et al.
(författare)
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1/f Noise and Dark Current Correlation in Midwave InAs/GaSb Type-II Superlattice IR Detectors
- 2021
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Ingår i: Physica Status Solidi (a) applications and materials science. - : Wiley-VCH Verlag. - 1862-6300 .- 1862-6319. ; 218:3, s. 2000557-
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Tidskriftsartikel (refereegranskat)abstract
- Herein, results from noise and dark current density studies on InAs/GaSb type-II superlattice IR detectors are presented. The activation energy of the dark current density is used to identify the dominating dark current mechanisms (generation–recombination (GR), tunneling, or diffusion dark current) as a function of temperature and bias. The bias evolution of the power spectral density (PSD) is measured in dark conditions for several temperatures. At the operating bias of the detectors, the arrays show a white noise–dominated spectrum up to 100 K with a minor 1/f contribution (corner frequency around 10 Hz), while for higher temperatures the spectra are 1/f dominated. The 1/f noise component is compared to the dominating dark current mechanism in the same temperature and bias regimes. A strong correlation between the 1/f noise component and the dominating dark current (I) is found, with the PSD proportional to I for tunneling currents and I2 for GR and diffusion currents. Very low noise coefficients of αGR = 4.8 × 10−9 Hz−1, αdiff = 1.9 × 10−10 Hz−1, and αtun = 2.1 × 10−16 A Hz−1 are observed for these detectors.
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| 6. |
- Ramos Santesmases, David, et al.
(författare)
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Two-step etch in n-on-p type-II superlattices for surface leakage reduction in mid-wave infrared megapixel detectors
- 2023
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Ingår i: Opto-Electronics Review. - : Polish Academy of Sciences Chancellery. - 1230-3402 .- 1896-3757. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the potential of p-type InAs/GaSb superlattice for the fabrication of full mid-wave megapixel detectors with n-on-p polarity. A significantly higher surface leakage is observed in deep-etched n-on-p photodiodes compared to p-on-n diodes. Shallow-etch and two-etch-step pixel geometry are demonstrated to mitigate the surface leakage on devices down to 10 mu m with n-on-p polarity. A lateral diffusion length of 16 mu m is extracted from the shallow etched pixels, which indicates that cross talk could be a major problem in small pitch arrays. Therefore, the two-etch-step process is used in the fabrication of 1280 x 1024 arrays with a 7.5 mu m pitch, and a potential operating temperature up to 100 K is demonstrated.
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| 7. |
- Sugiyama, Jun, et al.
(författare)
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Unveiled magnetic transition in Na battery material : mu+SR study of P2-Na0.5VO2
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:24, s. 18531-18537
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the microscopic magnetic nature of a novel Na battery material, P2-Na0.5VO2, in which V ions form a two-dimensional triangular lattice, by means of muon-spin rotation and relaxation (mu+SR) measurements down to 50 mK. Although magnetization measurements indicated the presence of an antiferromagnetic transition at 13 K, the internal magnetic field due to the formation of magnetic order appears not at 13 K but at 2 K. Furthermore, the magnetic order is found to have a wide field distribution even at 50 mK. Such wide field distribution is reasonably explained by a combination of multiple muon sites and the formation of a long-range magnetic order, while the reliable spin structure is still unknown.
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