Extended wavelength infrared photodetectors

Abstract

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.

Dark current and photoresponse characteristics of extended wavelength infrared photodetectors

“…For LH1002, the spectral range of the photoresponse was also in good agreement 13 with the designed value of ~0.30 eV, due to the absence of an energy offset ( E). However, 15SP3 (with an energy offset of E ~0.19 eV)…”

“…The extension of the photoresponse beyond is affected by the operating temperature, 13 possibly due to a less efficient hot-cold carrier energy transfer mechanism, and a reduced lifetime of the hot carriers with increasing temperature. Fig.…”

“…However, to achieve such an extended wavelength photoresponse, an energy offset ( E) between the injector-emitter and emitter-collector barriers is necessary. 13 At high values of E, the detector then operates under both positive and negative applied biases, and also in a photovoltaic mode. 13 In this paper, we present a study of the dark current of an extended wavelength photodetector, in the temperature range 10 -100K.…”

“…13 At high values of E, the detector then operates under both positive and negative applied biases, and also in a photovoltaic mode. 13 In this paper, we present a study of the dark current of an extended wavelength photodetector, in the temperature range 10 -100K. We find that the fit of the measured dark current, obtained through a 3D carrier drift model, agrees well with the designed value of ~ 0.40 eV (~3.1 µm).…”

Year in Review

“…13 The active electro-optical sensing special section included top-cited papers on hyperentanglement 14 and deep turbulence wavefront sensing, 15 while papers on anisoplanatic imaging through turbulence 9 (the only top-ten downloaded and cited) and atmospheric turbulence mitigation algorithms 16 from the long-range imaging special section were part of the list. The remainder included a paper on extended wavelength infrared photodetectors 17 from the infrared detectors special section, along with regular papers on binary holograms for depth visualization 18 and channel capacity of optical data links. 19 Six of these ten papers are available with open access.…”