| 1. |
- Delmas, M., et al.
(författare)
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HOT MWIR T2SL detectors to reduce system : Size, weight, and power
- 2021
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Ingår i: Sensors, Systems, and Next-Generation Satellites XXV. - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (refereegranskat)abstract
- In 2019, IRnova launched a full-scale production of a reduced size, weight and power integrated detector dewar cooler assemblies (Oden MW; VGA format with 15 μm pixel pitch) covering the full mid-wavelength infrared spectral domain (3.7 μm - 5.1 μm). Oden MW exhibits excellent performance with operating temperatures up to 110 K at F/5.5 with typical values of temporal and spatial noise equivalent temperature of 22 mK and 7 mK, respectively, and an operability higher than 99.85%. More recently, IRnova developed a new detector design with a cut-off wavelength of 5.3 μm which can potentially allow an operating temperature of the detector up to 150K with excellent performance demonstrated on single pixels with a quantum efficiency as high as 46% at 4 μm without antireflection coating, a turn on bias lower than -100 mV and a dark current density as low as 8 × 10-6 A/cm2, which is a factor of < 5 higher than Rule07. The dark current was also found independent of the device size ranging from 10 μm to 223 μm indicating that surface leakage currents are not limiting the dark current. The achievable operating temperature of an FPA made of this new detector design has been estimated to be <150 K with F/5.5 optics. These outstanding results demonstrate that this new generation of detector design is an excellent candidate for future high operating temperature and high-definition focal plane array.
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| 2. |
- Ramos Santesmases, David, et al.
(författare)
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Optical concentration in fully delineated mid-wave infrared T2SL detectors arrays
- 2023
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 123:18
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Tidskriftsartikel (refereegranskat)abstract
- The dependence of quantum efficiency (QE) on fill factor and pixel pitch is studied theoretically and experimentally in fully delineated type-II superlattice (T2SL) detectors. Theoretically, a 2-dimensional simulation model is used to compute the absorption in the array geometry, which shows an insensitivity of the optical response to the fill factor. This is a result of the photodiode array (PDA) geometry concentrating the light in the pixel area. QE measurements on PDAs with varying pixel pitch (from 225 to 10 μm) and fill factors (from 98% to 64%) confirm this independence of the QE on the fill factor and results in a 50% increase in the photocurrent density in 10 μm pitch PDAs compared to 225 μm pitch PDAs. Furthermore, measurements of the dark current density vs pixel size revealed an absence of surface leakage in these PDAs, which, combined with the increased photocurrent density results in an improved signal-to-noise ratio when reducing the pitch in these T2SL detectors. Finally, this result resolves the QE-modulation transfer function trade-off, as the electrical isolation of the pixel is carried out without impacting the QE of the array.
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| 3. |
- Ramos Santesmases, David, et al.
(författare)
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Simulation and Characterization of the Modulation Transfer Function in Fully Delineated Type-II Superlattices Infrared Detectors
- 2024
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Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 71:4, s. 2459-2464
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Tidskriftsartikel (refereegranskat)abstract
- The modulation transfer function (MTF) in fully delineated 15 μ m pitch type-II superlattice (T2SL) mid-wave infrared (IR) detectors is studied theoretically and experimentally. Theoretically, a 2-D model to simulate the spot scan (SS) profile is presented and used to compute the MTF as a function of the wavelength and the array geometry (pitch size, trench width). The dependence of the detector trench on the MTF is also evaluated experimentally by the edge spread function (ESF) method according to the ISO12233 standard. The experimental results show an excellent agreement with the theoretical model, reporting an MTF of 0.61 and 0.60 at the Nyquist frequency for 1 and 2 μ m trench, respectively. With the simulation model, the effect of the increased optical crosstalk for smaller pixel pitch is discussed as a function of the trench width (0.5, 1, and 2 μ m) and incidence angle up to ± 30 ∘ . Simulation results show MTF values at the Nyquist frequency between 0.61–0.62, 0.58–0.60, and 0.55–0.57 with an average degradation of 1%, 2%, and 7% at an angle of ± 30 ∘ compared to normal incidence for the 10, 7.5, and 5 μ m pitch, respectively.
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| 4. |
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| 5. |
- Höglund, Linda, 1974-, et al.
(författare)
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Bias and temperature dependence of the escape processes in quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 93:10, s. 103501-
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Tidskriftsartikel (refereegranskat)abstract
- The performance of quantum dots-in-a-well infrared photodetectors (DWELL IPs) has been studied by means of interband and intersubband photocurrent measurements as well as dark current measurements. Using interband photocurrent measurements, substantial escape of electrons from lower lying states in the DWELL structure at large biases was revealed. Furthermore, a significant variation in the escape probability from energy states in the DWELL structure with applied bias was observed. These facts can explain the strong temperature and bias dependence of both photocurrent and dark currents in DWELL IPs.
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| 6. |
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| 7. |
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| 8. |
- Höglund, Linda, et al.
(författare)
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Studies of photocurrent and dark current in quantum dots-in-a-well infrared photodetectors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The performance of quantum dots-in-a-well infrared photodetectors (DWELL IPs) has been studied by means of interband and intersubband photocurrent measurements as well as dark current measurements. Using interband photocurrent measurements, substantial escape of electrons from lower lying states in the DWELL structure at large biases was revealed. Furthermore, a significant variation of the escape probability from energy states in the DVELL sturcture with voltage was observed. These facts could be possible explanations to the strong temperature and voltage dependence of hoth photocurrent and dark current in DWELL IPs. In a comparison between DWELL IPs and quantum well infrared photocdetectors (QWIPs), the dark current was shown to be considerably lower in DWELL IPs than in QWIPs, but alos the responsivity was low in comparison to QWIPs.
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| 9. |
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| 10. |
- Claesson, Åsa, et al.
(författare)
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Internal Electrode Fiber Polarization Controller
- 2003
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Ingår i: Conf Opt Fiber Commun Tech Dig Ser. ; , s. 39-40
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Konferensbidrag (refereegranskat)abstract
- Potentially low-cost polarization controllers were studied with a current-driven internal electrode fibers. The return loss was determined for the device. An EDFA was used as light source, and five devices were constructed and tested. The polarization dependent loss (PDL) of the polarization controllers was measured between 1530 nm and 1570 nm using the Jones-matrix method. The response times for the controllers was found to be relatively slow. The rise time of the optical response was significantly improved by overshooting the current pulse.
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| 11. |
- Höglund, Linda, 1974-, et al.
(författare)
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Quantum dots-in-a-well infrared photodetectors for long wavelength infrared detection
- 2006
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Ingår i: Proceedings of SPIE. - Bellingham, Wash. : SPIE - International Society for Optical Engineering. - 9780819464996 ; 6401, s. 1-640109
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Konferensbidrag (refereegranskat)abstract
- We report on a quantum dots-in-a-well infrared photodetector (DWELL QDIP) grown by metal organic vapor phase epitaxy. The DWELL QDIP consisted of ten stacked InAs/In0.5Ga0.85As/GaAs QD layers embedded between n-doped contact layers. The density of the QDs was about 9 × 10 10 cm-2 per QD layer. The energy level structure of the DWELL was revealed by optical measurements of interband transitions, and from a comparison with this energy level scheme the origin of the photocurrent peaks could be identified. The main intersubband transition contributing to the photocurrent was associated with the quantum dot ground state to the quantum well excited state transition. The performance of the DWELL QDIPs was evaluated regarding responsivity and dark current for temperatures between 15 K and 77 K. The photocurrent spectrum was dominated by a LWIR peak, with a peak wavelength at 8.4 μm and a full width at half maximum (FWHM) of 1.1 μm. At an operating temperature of 65 K, the peak responsivity was 30 mA/W at an applied bias of 4 V and the dark current was 1.2×10-5 A/cm2. Wavelength tuning from 8.4 μm to 9.5 μm was demonstrated, by reversing the bias of the detector.
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| 12. |
- Martijn, H., et al.
(författare)
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Development of IR imaging at IRnova
- 2009
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Ingår i: Infrared Technology and Applications XXXV. - : SPIE.
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Konferensbidrag (refereegranskat)abstract
- Historically IRnova has exclusively been a company, focused on manufacturing of QWIP detectors. Nowadays, besides continuous improvements of the performance of QWIP FPAs and development of new formats IRnova is involved in development of QWIP detectors for special applications and has started the development of the next generation infrared detectors, as well. In the light of the development of new formats we validate experimentally theoretical calculations of the response of QWIPs for smaller pixel size. These results allow for the development of high performance megapixel QWIP FPA that exhibit the high uniformity and operability QWIP detectors are known for. QWIP is also being considered for space applications. The requirements on dark current and operating temperature are however much more stringent as compared to the terrestrial applications. We show ways to improve the material quality with as a result a higher detector operating temperature. IRnova is also looking at antimony-based strained superlattice material for the LWIR region together with partners at theIMAGIC centre of excellence. One of the ways to overcome the problem with surface currents is passivating overgrowth. We will report the status and results of overgrowing the detector mesas with AlGa(As)Sb in a MOVPE system. At the same centre of excellence a novel material concept is being developed for LWIR detection. This new material contains a superlattice of vertically aligned and electronically coupled InAs and GaSb quantum dots. Simulations show that it should be possible to have LWIR detection in this material. We will present the current status and report results in this research.
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