Articles you may be interested inResonant cavity enhanced In As ∕ In 0.15 Ga 0.85 As dots-in-a-well quantum dot infrared photodetector Effects of Si doping on normal incidence In As ∕ In 0.15 Ga 0.85 As dots-in-well quantum dot infrared photodetectors J. Appl. Phys. 99, 083105 (2006); 10.1063/1.2189973Normal-incidence InAs / In 0.15 Ga 0.85 As quantum dots-in-a-well detector operating in the long-wave infrared atmospheric window (8-12 μm) InAs quantum dot infrared photodetectors with In 0.15 Ga 0.85 As strain-relief cap layers
We report a three-color InAs/InGaAs quantum-dots-in-a-well detector with center wavelengths at ∼3.8, ∼8.5, and ∼23.2 μm. We believe that the shorter wavelength responses (3.8 and 8.5 μm) are due to bound-to-continuum and bound-to-bound transitions between the states in the dot and states in the well, whereas the longer wavelength response (23.2 μm) is due to intersubband transition between dot levels. A bias-dependent activation energy ∼100 meV was extracted from the Arrhenius plots of the dark currents, which is a factor of 3 larger than that observed in quantum-well infrared photodetectors operating at comparable wavelengths.
Quantum-dot infrared photodetectors (QDIPs) exhibit a bias-dependent shift in their spectral response. In this paper, a novel signal-processing technique is developed that exploits this bias-dependent spectral diversity to synthesize measurements that are tuned to a wide range of user-specified spectra. The technique is based on two steps: The desired spectral response is first optimally approximated by a weighted superposition of a family of bias-controlled spectra of the QDIP, corresponding to a preselected set of biases. Second, multiple measurements are taken of the object to be probed, one for each of the prescribed biases, which are subsequently combined linearly with the same weights. The technique is demonstrated to produce a unimodal response that has a tunable FWHM (down to ⌬ ϳ 0.5 m) for each center wavelength in the range 3-8 m, which is an improvement by a factor of 4 over the spectral resolution of the raw QDIP.
Articles you may be interested inAn intermediate-band-assisted avalanche multiplication in InAs/InGaAs quantum dots-in-well infrared photodetector Appl. Phys. Lett. 98, 073504 (2011); 10.1063/1.3554758Low-strain In As ∕ In Ga As ∕ Ga As quantum dots-in-a-well infrared photodetector
Influence of quantum well and barrier composition on the spectral behavior of InGaAs quantum dots-in-a-well infrared photodetectorsDemonstration of a 320 × 256 two-color focal plane array using InAs/InGaAs quantum dots in well detectors Appl. Phys. Lett. 86, 193501 (2005); 10.1063/1.1924887 Three-color (λ p1 3.8μ m , λ p2 8.5μ m , and λ p3 23.2μ m ) InAs/InGaAs quantum-dots-in-a-well detector Appl.
Theoretical modeling and experimental characterization of InGaAs∕GaAs quantum dots-in-a-well (DWELL) intersubband heterostructures, grown by molecular beam epitaxy are reported. In this heterostructure, the self-assembled dots are confined to the top half of a 110Å InGaAs well which in turn is placed in a GaAs matrix. Using transmission electron microscopy, the quantum dots are found to be pyramidal in shape with a base dimension of 110Å and height of 65Å. The band structure for the above mentioned DWELL heterostructure was theoretically modeled using a Bessel function expansion of the wave function. The energy levels of the three lowest states of the conduction band of the quantum dot are calculated as a function of the electric field. Intersubband n-i-n detectors were fabricated using a ten layer DWELL heterostructure. The spectral response of the detector is measured at a temperature between 30 and 50 K and compared with the prediction of our theoretical model.
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