共查询到20条相似文献,搜索用时 15 毫秒
1.
D.Z.-Y. Ting Y.-C. Chang S.V. Bandara C.J. Hill S.D. Gunapala 《Infrared Physics & Technology》2007,50(2-3):136-141
We examined theoretically band structure and discrete dopant effects in the quantum well infrared photodetector (QWIP) and the quantum dot infrared photodetector (QDIP). We find that in QWIPs discrete dopant effects can induce long wavelength infrared absorption through impurity assisted intra-subband optical transitions. In QDIPs, we find that a strategically placed dopant atom in a quantum dot can easily destroy the symmetry and modify the selection rule. This mechanism could be partially responsible for normal incidence absorption observed in low-aspect-ratio quantum dots. 相似文献
2.
J.Y. Andersson L. H?glund B. Noharet Q. Wang P. Ericsson S. Wissmar C. Asplund H. Malm H. Martijn M. Hammar O. Gustafsson S. Hellstr?m H. Radamson P.O. Holtz 《Infrared Physics & Technology》2010,53(4):227-230
Acreo has a long tradition of working with quantum structure based infrared (IR) detectors and arrays. This includes QWIP (quantum well infrared photodetector), QDIP (quantum dot infrared photodetector), and InAs/GaInSb based photon detectors of different structure and composition. It also covers R&D on uncooled microbolometers. The integrated thermistor material of such detectors is advantageously based on quantum structures that are optimised for high temperature coefficient and low noise. Especially the SiGe material system is preferred due to the compatibility with silicon technology. The R&D work on IR detectors is a prominent part of Acreo’s centre of excellence “IMAGIC” on imaging detectors and systems for non-visible wavelengths. IMAGIC is a collaboration between Acreo, several industry partners and universities like the Royal Institute of Technology (KTH) and Linköping University. 相似文献
3.
Alexandru Nedelcu Eric Costard Philippe Bois Xavier Marcadet 《Infrared Physics & Technology》2007,50(2-3):227-233
Recent results obtained on building blocks for future third generation infrared focal plane arrays (FPAs) are presented. Our approach concerning the FPA performance assessment and small pixels modelling is exposed. We also demonstrate the ability of the quantum well infrared photodetector technology to answer the needs for compact (20 μm pitch) polarimetric FPAs. Finally, we present our first results on mid-wave infrared detectors at wavelengths below 4.2 μm. 相似文献
4.
Narrow spectral band infrared detectors are required for multispectral infrared imaging. We review the first photovoltaic resonant cavity enhanced detectors (RCED) for the mid-IR range. The lead-chalcogenide (PbEuSe) photodetector is placed as a very thin layer inside an optical cavity. At least one side is terminated with an epitaxial Bragg mirror (consisting of quarter wavelength PbEuSe/BaF2 pairs), while the second mirror may be a metal. Linewidths are as narrow as 37 nm at a peak wavelength of 4400 nm, and peak quantum efficiencies up to above 50% are obtained. 相似文献
5.
Agafonov IN Chekhova MV Iskhakov TS Penin AN Rytikov GO Shcherbina OA 《Optics letters》2011,36(8):1329-1331
We report testing of the new absolute method of photodetector calibration based on the difference-signal measurement for two-mode squeezed vacuum by comparison with the traditional absolute method based on coincidence counting. Using low-gain parametric downconversion, we have measured the quantum efficiency of a counting detector by both methods. The difference-signal method was adapted for the counting detectors by taking into account the dead-time effect. 相似文献
6.
The novel approach proposed in the present study is to use graphene based materials in the structure of the available infrared photo detectors in order to improve their parameters. The photo detector under study is PIN photodiode photodetector with no internal gain, but a very wide wavelength. In this paper, we have shown that the graphene-based detectors can exhibit high responsivity and detectivity at elevated temperatures in a wide radiation spectrum due to high values of the quantum efficiency and relatively low rates of thermo generation which lead them to surpass other detectors substantially. 相似文献
7.
Armchair graphene nanoribbons (A-GNRs) are an alternative material to use in novel infrared photodetectors, because of their tunable energy gap in the infrared spectrum, and their high quantum efficiency. In this paper, an A-GNR p–i–n structure with all three structural families, different width, and different number of layers to use in IR detectors have been investigated. With calculating the band structure and energy gap using the tight-binding model and by including the edge deformation, the optical absorption in the single electron approximation has been obtained by calculating the optical conductance. Finally, we have calculated the quantum efficiency and the optical responsivity of A-GNR based IR photodetector as a function of incident photon energy, temperature, nanoribbon width and the number of layers. Results show that the responsivity of the A-GNR based IR photodetector increase by increasing the width and number of layers and decrease by increasing the temperature. 相似文献
8.
The advent of nanophotonics allows devising and fabricating optical antenna as the advanced optical structures that can enhance light–matter interaction in quantum structures such as quantum wells. Improving infrared photodetector performance is discussed theoretically in this paper. We also investigate our recent demonstration of optical antenna integrated on quantum well infrared photodetector which improves the performance of the detector as can be evidence in responsivity of the detector. 相似文献
9.
Narrow spectral band infrared detectors are required for multispectral infrared imaging. Wavelength selectivity can be obtained
by placing passive line filters in front of the detectors, or, the preferred choice, by making the detectors themselves wavelength
selective. We review the first photovoltaic resonant cavity enhanced detectors (RCED) for the mid-IR range. The lead-chalcogenide
(PbEuSe) photodetector is placed as a very thin layer inside an optical cavity. At least one side is terminated with an epitaxial
Brugg mirror (consisting of quarter wavelength PbEuSe/BaF2 pairs), while the second mirror may be a metal. Linewidths are as narrow as 37 nm at a peak wavelength of 4400 nm, and peak
quantum efficiencies up to above 50% are obtained.
The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570B (2005). 相似文献
10.
A design for an IR photodetector is proposed and described that uses an array of II–VI semiconductor quantum wire heterostructures and that uses intersubband transitions in the conduction band of the wires as the IR detection mechanism. The detection mechanism of these quantum wire infrared detectors (QRIP) is similar to that used in quantum well infrared photodetectors (QWIP) but important differences arise due to the further confinement of the electrons in an additional dimension. QWIPs are briefly described, including their undesirable aspects and how QRIPs offer solutions to these problematic issues. The electron quantum states, absorption and other important aspects of several QRIP designs are calculated using analytical and finite difference techniques. A potential design for a focal plane array using QRIPs is described that uses a nanopatterned alumina template for DC electrodeposition of II–VI semiconductor quantum wires oriented normal to the substrate. 相似文献
11.
A. G. U. Perera 《Opto-Electronics Review》2006,14(2):99-108
The work describes multiband photon detectors based on semiconductor micro-and nano-structures. The devices considered include
quantum dot, homojunction, and heterojunction structures. In the quantum dot structures, transitions are from one state to
another, while free carrier absorption and internal photoemission play the dominant role in homo or heterojunction detectors.
Quantum dots-in-a-well (DWELL) detectors can tailor the response wavelength by varying the size of the well. A tunnelling
quantum dot infrared photodetector (T-QDIP) could operate at room temperature by blocking the dark current except in the case
of resonance. Photoexcited carriers are selectively collected from InGaAs quantum dots by resonant tunnelling, while the dark
current is blocked by AlGaAs/InGaAs tunnelling barriers placed in the structure. A two-colour infrared detector with photoresponse
peaks at ∼6 and ∼17 μm at room temperature will be discussed. A homojunction or heterojunction interfacial workfunction internal
photoemission (HIWIP or HEIWIP) infrared detector, formed by a doped emitter layer, and an intrinsic layer acting as the barrier
followed by another highly doped contact layer, can detect near infrared (NIR) photons due to interband transitions and mid/far
infrared (MIR/FIR) radiation due to intraband transitions. The threshold wavelength of the interband response depends on the
band gap of the barrier material, and the MIR/FIR response due to intraband transitions can be tailored by adjusting the band
offset between the emitter and the barrier. GaAs/AlGaAs will provide NIR and MIR/FIR dual band response, and with GaN/AlGaN
structures the detection capability can be extended into the ultraviolet region. These detectors are useful in numerous applications
such as environmental monitoring, medical diagnosis, battlefield-imaging, space astronomy applications, mine detection, and
remote-sensing.
The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570W (2005). 相似文献
12.
In this work, we have studied the inter- and intra-subband scattering of hot electrons in quantum wells using the hot electron-neutral acceptor luminescence technique. We have observed direct evidence of the emission of confined optical phonons by hot electrons excited slightly above the n=2 subband in GaAs/Al0.37Ga0.63As quantum wells. Scattering rates of photoexcited electrons via inter- and intra-subband LO phonon emission were calculated based on the dielectric continuum model. We found that, for wide wells with the Al composition of our experiments, both the calculated and experimental results suggest that the scattering of the electrons is dominated by the confined LO phonon mode. In the calculations, scatterings among higher subbands are also dominated by the same type of phonon at well width of 10 nm. 相似文献
13.
W. Z. Shen 《International Journal of Infrared and Millimeter Waves》2000,21(11):1739-1746
The recent developments of semiconductor infrared detectors in extending the wavelength coverage and improving the focal plane array (FPA) performance are reviewed. The emphasis is on the GeSi/Si heterojunction infrared photoemission detectors (HIPs), GaAs/AlGaAs quantum well infrared photodetecots (QWIPs), Si, Ge and GaAs blocked impurity band detectors (BIBS), and Si and GaAs homojunction interfacial work-function internal photo-emission (HIWIP) far-infrared (FIR) detectors. The advantages, current status, and potential limitations of these infrared detectors have also been discussed. 相似文献
14.
《Infrared physics》1993,34(2):153-161
We propose a differentially strained p-doped quantum well infrared (IR) photodetector that achieves high performance specifications. We examine key device and material considerations for such a detector for near 10 μm detection. We calculate that through differential strain, this novel detector has improved gain and substantially reduced dark current over previous quantum well IR photodetectors, while being able to detect normal incident light. 相似文献
15.
A method to extend wavelength into middle-wavelength infrared based on InAsSb/(Al)GaSb interband transition quantum well infrared photodetector
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We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified In As Sb quantum well, Ga Sb is replaced with Al Sb/Al Ga Sb, the valence band of the barrier material is lowered, the first restricted energy level is higher than the valence band of the barrier material, the energy band structure forms type-II structure. The photocurrent spectrum manifest that the fabricated photodetector exhibits a response range from 1.9 μm to 3.2 μm with two peaks at 2.18 μm and 3.03 μm at 78 K. 相似文献
16.
17.
《Superlattices and Microstructures》2001,30(2):69-74
We study the optical transition between bound-to-continuum states in a GaAs/AlGaAs multiple quantum well infrared photodetector (QWIP) by analyzing three possible boundary conditions for the continuum states. Comparing with experimental results, it has been suggested that the Bloch-state boundary conditions are proper for continuum states in the QWIPs consisting of multiple quantum wells and the fine structures in the responsivity spectrum result from the energy dispersion relationship of the multiple quantum wells. 相似文献
18.
G. Ariyawansa A.G.U. Perera X.H. Su S. Chakrabarti P. Bhattacharya 《Infrared Physics & Technology》2007,50(2-3):156-161
Quantum dot structures designed for multi-color infrared detection and high temperature (or room temperature) operation are demonstrated. A novel approach, tunneling quantum dot (T-QD), was successfully demonstrated with a detector that can be operated at room temperature due to the reduction of the dark current by blocking barriers incorporated into the structure. Photoexcited carriers are selectively collected from InGaAs quantum dots by resonant tunneling, while the dark current is blocked by AlGaAs/InGaAs tunneling barriers placed in the structure. A two-color tunneling-quantum dot infrared photodetector (T-QDIP) with photoresponse peaks at 6 μm and 17 μm operating at room temperature will be discussed. Furthermore, the idea can be used to develop terahertz T-QD detectors operating at high temperatures. Successful results obtained for a T-QDIP designed for THz operations are presented. Another approach, bi-layer quantum dot, uses two layers of InAs quantum dots (QDs) with different sizes separated by a thin GaAs layer. The detector response was observed at three distinct wavelengths in short-, mid-, and far-infrared regions (5.6, 8.0, and 23.0 μm). Based on theoretical calculations, photoluminescence and infrared spectral measurements, the 5.6 and 23.0 μm peaks are connected to the states in smaller QDs in the structure. The narrow peaks emphasize the uniform size distribution of QDs grown by molecular beam epitaxy. These detectors can be employed in numerous applications such as environmental monitoring, spectroscopy, medical diagnosis, battlefield-imaging, space astronomy applications, mine detection, and remote-sensing. 相似文献
19.
A study of intersubband transitions in quantum well infrared detectors working at high temperatures has been reported. This study allows a greater tunability in the device designs, with the ability to control the peak wavelength, the absorption coefficient, the dark current, the quantum efficiency and the detectivity of the modeled structure operating around 3.3 μm wavelength. The detection energy and absorption coefficient dependences with an applied electric field are given. Then, the electro-optic performances of the modeled mid-infrared detector are estimated, the dark current dependence with the applied voltage and temperature as well as the quantum efficiency and the detectivity are investigated and discussed. High detectivities were found at high temperatures revealing the good performances of the designed photodetector, especially at 3.3 μm wavelength. 相似文献
20.
Sumith V. Bandara 《Infrared Physics & Technology》2009,52(6):299-303
Advancements in III–V semiconductor based, Quantum-well infrared photodetector (QWIP) and Type-II Strained-Layer Superlattice detector (T2SLS) technologies have yielded highly uniform, large-format long-wavelength infrared (LWIR) QWIP FPAs and high quantum efficiency (QE), small format, LWIR T2SLS FPAs. In this article, we have analyzed the QWIP and T2SLS detector level performance requirements and readout integrated circuit (ROIC) noise levels for several staring array long-wavelength infrared (LWIR) imaging applications at various background levels. As a result of lower absorption QE and less than unity photoconductive gain, QWIP FPAs are appropriate for high background tactical applications. However, if the application restricts the integration time, QWIP FPA performance may be limited by the read noise of the ROIC. Rapid progress in T2SLS detector material has already demonstrated LWIR detectors with sufficient performance for tactical applications and potential for strategic applications. However, significant research is needed to suppress surface leakage currents in order to reproduce performances at pixel levels of T2SLS FPAs. 相似文献