Terahertz absorption in AlGaAs films and detection using heterojunctions

Rinzan, M. B. M.; Perera, A. G. U.; Matsik, S. G.; Liu, H.C.; Buchanan, M.; Winckel, G. von; Stintz, A.; Krishna, S.

doi:10.1016/j.infrared.2005.02.025

Cited by 10 publications

(6 citation statements)

References 13 publications

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“…However, the limit of the spectral photoresponse of p-GaAs∕Al x Ga 1−x As detectors is normally determined by the activation energy 3 (Δ), defined as the interfacial energy gap at the emitter (absorber)/barrier interface; that is, the difference between the Fermi level in the p-GaAs emitter and the potential barrier in the Al x Ga 1−x As layer. Even though Δ can be adjusted to cover the mid-IR to far-IR spectral ranges, 4,5 lowering the value of Δ always leads to an increased dark current and an increase in the related noise levels. Recently, it was reported 6 that the wavelength threshold can be dramatically extended beyond the expected value of λ t .…”

Section: Introductionmentioning

confidence: 99%

Extended wavelength infrared photodetectors

Chauhan

Perera

et al. 2017

Opt. Eng

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Abstract. Extension of the wavelength threshold of an infrared detector beyond λ t ¼ hc∕Δ is demonstrated, without reducing the minimum energy gap (Δ) of the material. Specifically, a photodetector designed with Δ ¼ 0.40 eV, and a corresponding λ t ¼ 3.1 μm, was shown to have an extended threshold of ∼45 μm at 5.3 K, at zero bias. Under negative and positive applied bias, this range was further extended to ∼60 and ∼68 μm, respectively, with the photoresponse becoming stronger at increased biases, but the spectral threshold remained relatively constant. The observed wavelength extension arises from an offset between the two potential barriers in the device. Without the offset, another detector with Δ ¼ 0.30 eV showed a photoresponse with the expected wavelength threshold of ∼4 μm.

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Section: Introductionmentioning

confidence: 99%

Extended wavelength infrared photodetectors

Chauhan

Perera

et al. 2017

Opt. Eng

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“…The FIR absorption in AlGaAs is very similar to GaAs (Rinzan et al, 2005a) because of the very-low Al content giving performances similar to the devices with AlGaAs barriers. A practical lower limit for the Al fraction is around x ≥ 0.005, which corresponds to λ t ≤ 110 µm.…”

Section: Barrier Height Variation In Heiwipsmentioning

confidence: 68%

Homo- and Heterojunction Interfacial Workfunction Internal Photo-Emission Detectors from UV to IR

Perera¹

2011

Advances in Infrared Photodetectors

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“…Therefore, a p-GaAs layer absorbs a broad IR spectrum spanning shortwave IR (SWIR) to the very-long-wave IR (VLWIR) range. Whilst values of can be adjusted to cover the mid-IR to far-IR spectral ranges, 3,4 for the spectral photoresponse of p-GaAs/ Al x Ga 1-x As heterostructures-based IR photodetectors is still traditionally determined by interfacial energy gap ( ) at the emitter (absorber)/collector barrier interface.…”

Section: Introductionmentioning

confidence: 99%

Dark current and photoresponse characteristics of extended wavelength infrared photodetectors

Chauhan

Perera

et al. 2017

Journal of Applied Physics

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The dark current and spectral photoresponse threshold of a semiconductor photodetector are normally determined by the minimum energy gap ( ) of the material, or the interfacial energy gap of the heterostructure. In this manuscript, we discuss the performance of an asymmetric p-GaAs/Al x Ga 1-x As heterostructure-based infrared photodetector, which shows an extended wavelength threshold beyond the limit set by . The measured dark current was found to agree well with fits obtained from a 3D carrier drift model using the designed value of ~0.40 eV (~3.1 µm). In contrast, the spectral photoresponse showed extended wavelength thresholds of ~68 µm, ~45 µm, and ~60 µm at positive, zero, and negative biases, respectively, at 5.3K. For a reference (symmetric) photodetector, the dark current was fitted with the designed value of ~0.30 eV, and excellent agreement was obtained for both the measured dark current and spectral response. This underlies the advantage of using asymmetric infrared photo-detector designs, in which an extension to the detected wavelengths can be obtained with little compromise to the dark current characteristics.

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Terahertz absorption in AlGaAs films and detection using heterojunctions

Cited by 10 publications

References 13 publications

Extended wavelength infrared photodetectors

Extended wavelength infrared photodetectors

Homo- and Heterojunction Interfacial Workfunction Internal Photo-Emission Detectors from UV to IR

Dark current and photoresponse characteristics of extended wavelength infrared photodetectors

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