This PDF file contains the front matter associated with SPIE Proceedings Volume 9933, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.
Suspensions of HgTe colloidal quantum dots (CQD) are readily synthesized with infrared energy gaps between 3 and 12 microns. Infrared photodetection using dried films of these CQDs has been demonstrated up to a cutoff wavelength of 12 microns. The synthesis of CQDs and the fabrication of detector devices employ bench-top chemistry techniques, leading to the potential for the easy manufacture of infrared photon detecting imagers at low cost. Recent electrical and optical measurements of these CQD films are discussed. Recent successful prototypes of complete focal plane arrays from CQD films and commercially-available ROICs are also described.
This work presents the development of a quantum dot-based photosensitive film engineered to be integrated on standard CMOS process wafers. It enables the design of exceptionally high performance, reliable image sensors. Quantum dot solids absorb light much more rapidly than typical silicon-based photodiodes do, and with the ability to tune the effective material bandgap, quantum dot-based imagers enable higher quantum efficiency over extended spectral bands, both in the Visible and IR regions of the spectrum. Moreover, a quantum dot-based image sensor enables desirable functions such as ultra-small pixels with low crosstalk, high full well capacity, global shutter and wide dynamic range at a relatively low manufacturing cost. At InVisage, we have optimized the manufacturing process flow and are now able to produce high-end image sensors for both visible and NIR in quantity.
We have investigated the effect of implantation of Lithium ions of varying energies from 20 keV to 50 keV at fixed dose 2 × 1012 ions/cm2 on InAs/GaAs QDs. Temperature dependent (15K-300K) photoluminescence (PL) study was carried for all samples. Implantation resulted consistent degradation in PL efficiency with rise in energy of ions. The same trend was also observed while varying the fluence at fixed energy. Suppression in PL intensity might be due to creation of defects/damage profile in the vicinity of the QDs which act as trapping centers for photocarriers. Implantation also resulted in decrease of activation energies from 230 meV (as-grown) to 35 meV (50 keV) indicating reduced carriers confinement in QDs. The 50 keV sample demonstrated the mild red shift in PL spectra which is probably originated from atomic interdiffussion between dots and barrier layer caused by local heat generation.
One of JAXA’s future missions, using an imaging Fourier Transform Spectrometer (FTS), require the focal plane array (FPA) that has high sensitivity and a very long-wavelength infrared (VLWIR) cutoff wavelength. Since a Type-II superlattice (T2SL) is the only known infrared material to have a theoretically predicted performance superior to that of HgCdTe and the cutoff wavelength can be tailored in the wavelength region of 3-30 μm, we started the research and development of the T2SL detector in 2009. In order to confirm our final goal which is to realize an FPA with a cutoff wavelength of 15 μm, we fabricated InAs/GaInSb T2SL infrared detectors with a cutoff wavelength of 15 μm. We show the results of the dark current and responsivity measurement of single pixel detectors and the development status of FPAs including the image taken by a 320 × 256 InAs/GaInSb T2SL FPA with a cutoff wavelength of 15 μm.
This paper will report on the proton, and total ionizing dose characterizations of an MWIR nBn detector array. The FPA was fabricated using MWIR nBn infrared detectors, which have a cutoff wavelength of approximately 5.0 μm at 120 K. Full radiometric characterizations were performed at multiple total ionizing dose levels to determine the impact of the radiation on the FPA noise, responsivity, NEI, and dynamic range. Displacement damage effects on the MWIR nBn detectors was evaluated at a proton energy of 63 MeV. These displacement damage effects primarily degrade the performance of the detector array through increased dark current, generation of "hot pixels" due to elevated dark current that form a tail to the dark current distribution, reduction in responsivity, and degraded uniformity. The majority of the performance degradation of the MWIR nBn detectors due to proton interactions can be attributed to a reduction in the minority carrier lifetime in the absorber region of the nBn detector.
Proc. SPIE 9933, Center for Semiconductor Materials and Device Modeling: expanding collaborative research opportunities between government, academia, and industry, 993308 (26 September 2016); doi: 10.1117/12.2240312
To increase Soldier readiness and enhance situational understanding in ever-changing and complex environments, there is a need for rapid development and deployment of Army technologies utilizing sensors, photonics, and electronics. Fundamental aspects of these technologies include the research and development of semiconductor materials and devices which are ubiquitous in numerous applications. Since many Army technologies are considered niche, there is a lack of significant industry investment in the fundamental research and understanding of semiconductor technologies relevant to the Army. To address this issue, the US Army Research Laboratory is establishing a Center for Semiconductor Materials and Device Modeling and seeks to leverage expertise and resources across academia, government and industry. Several key research areas—highlighted and addressed in this paper—have been identified by ARL and external partners and will be pursued in a collaborative fashion by this Center. This paper will also address the mechanisms by which the Center is being established and will operate.
An intrinsic signal amplification mechanism, namely cycling excitation process (CEP), has been demonstrated in a heavily doped and heavily compensated silicon p-n junction diode. The physical process amplifies photo-generated signal at low bias (<5V) and produces ultralow excess noise at least partially attributed to an internal stabilization mechanism via electron-phonon interactions. Auger excitation, which can be calculated with Fermi Golden rule and quasi pseudopotential, and localized carrier ionization by phonon absorption are considered two key processes responsible for the unique device characteristics. A partially compensated p-n junction silicon diode based on the proposed CEP principle has shown high gain of ~6000 at -5V and an excess noise factor as low as 3.5 at this gain level, measured at 635nm wavelength and 1KHz for potential imaging applications.
Intrinsix has developed a Digital Focal Plane Array (DFPA) architecture based on a novel piecewise linear Log2 ADC (LADC) with “lossless” analog compression which enables ultra-high dynamic range ROICs that use less power than other extended dynamic range technologies. The LADC provides dynamic range of 126dB with a constant 75dB SNR over the entire frame. The companding 13bit mantissa, 3bit radix per pixel LADCs compress the 21bit signals into efficient 16 bit data words. The Read Out IC (ROIC) is compatible with most IR and LWIR detectors including two-color SLS (photodiode) and uBolometers. The DFPA architecture leverages two (staggered frame prime and redundant) MIPI CSI-3 interfaces to achieve full HD DFPA at 1000 frames/sec; an equivalent uncompressed data rate of 100Gb/sec.
The LADC uses direct injection into a moderate sized integrating capacitor and several comparators create a stream of multi-bit data values. These values are accumulated in an SRAM based log2ALU and the radix of the ALU is combined with the data to generate a feedback current to the integrating capacitor, closing the delta loop. The integration time and a single pole low pass IIR filter are configurable using control signals to the log2ALU. The feedback current is at least partially generated using PWM for high linearity.
Quantum Cascade Lasers (QCL) have seen tremendous recent application in the realm of Defence and Security. And, in many instances replacing traditional solid state lasers as the source of choice for Countermeasures, Remote Sensing, In-situ Sensing, Through-Barrier Sensing, and many others. Following their development and demonstration in the early 1990's, QCL’s reached some maturity and specific defence and security application prior to 2005; with much initial development fostered by DARPA initiatives in the US, dstl, MoD, and EOARD funding initiatives in the UK, and University level R&D such as those by Prof Manijeh Razeghi at Northwestern University , and Prof Ted Masselink at Humboldt University . As QCL’s provide direct mid-IR laser output for electrical input, they demonstrate high quantum efficiency compared with diode pumped solid state lasers with optical parametric oscillators (OPOs) to generate mid-Infrared output. One particular advantage of QCL's is their very broad operational bandwidth, extending from the terahertz to the near-infrared spectral regions. Defence and Security areas benefiting from QCL's include: Countermeasures, Remote Sensing, Through-the-Wall Sensing, and Explosive Detection.
All information used to construct this paper obtained from open sources.
High-fidelity, broadly-tunable quantum cascade lasers (QCLs) are replacing thermal light sources in next-generation infrared chemical imaging and microscopy instrumentation. Their superior spectral brightness, beam quality, and reliability are enabling new applications in biomedical, pharmaceutical, and industrial markets which demand substantially better noise performance, higher throughput, and ease-of-use. In this talk we will discuss the state-of-the-art in QCL source technology and describe our systems approach to leveraging QCL sources in the next-generation of infrared chemical imaging microscopes.
Sofradir presented its product Scorpio LW based on a p on n HgCdTe technology. This product is in production with a TV format, 15μm pitch. This product was developed and optimized in the framework of the joint laboratory between Sofradir and the CEA-LETI.
The p on n technology is based on an In doped absorbing material and an As implanted junction area. This architecture allows decreasing both dark current and series resistance compared to the legacy n on p technology based on Hg vacancies. This technology demonstrated an operating temperature up to 100K and a typical operability over 99.5%.
Some applications require a lower dark current in the range 90K to 110K, a lower average noise level and a lower number of noise defects than the present ones. In order to address these specific requirements, Sofradir performed some technological improvements.
In this paper, the technological improvements are briefly described. These technological tunings led to a 40% decrease of dark current at 110K. Both noise level and number of noise defects are kept constant in the range 90K to 110K. These improvements are paving the way to a further increase of operating temperature for long wave (LW) devices.
Pure extra virgin olive oil (EVOO) is mixed with cheaper edible oils and samples are kept inside clear glass containers, while a 785nm Raman system is used to take measurements as Raman probe is placed against glass container. Several types of oils at various concentrations of adulteration are used. Ratios of peak intensities are used to analyze raw data, which allows for quick, easy, and accurate analysis. While conventional Raman measurements of EVOO may take as long as 2 minutes, all measurements reported here are for integration times of 15s. It is found that adulteration of EVOO with cheaper oils is detectable at concentrations as low as 5% for all oils used in this study.