Abstract:We report the demonstration of high-performance long-wavelength infrared (LWIR) nBn photodetectors based on InAs/InAs1− xSbx type-II superlattices. A new saw-tooth superlattice design was used to implement the electron barrier of the photodetectors. The device exhibited a cut-off wavelength of ∼10 μm at 77 K. The photodetector exhibited a peak responsivity of 2.65 A/W, corresponding to a quantum efficiency of 43%. With an R × A of 664 Ω·cm2 and a dark current density of 8 × 10−5 A/cm2, under −80 mV bias voltag… Show more
“…Pristine FASnI 3 is unstable in air because Sn 2+ can be easily oxidized to Sn 4+ . [4][5][6][7] Thus, it is necessary to develop the next-generation PDs based on novel materials and designs. [32] The device based on the stable FASnI 3 layer displays high responsivity in a broad wavelength region from 300 to 1000 nm with the maximum responsivity and gain over 10 5 A W −1 and 10 5 , respectively, at a low working voltage.…”
Section: Doi: 101002/advs201900751mentioning
confidence: 99%
“…Photodetectors (PDs) have been widely used for various applications, such as optical communication, biomedical imaging, health care monitoring, video imaging, building inspection, and night vision . However, commercial III–V compound or Si‐based PDs normally suffer from relatively low response, high driving voltage, limited spectral response, and expensive fabrication . Thus, it is necessary to develop the next‐generation PDs based on novel materials and designs.…”
Organic–inorganic hybrid perovskites have emerged as promising functional materials for high‐performance photodetectors. However, the toxicity of Pb and the lack of internal gain mechanism in typical perovskites significantly hinder their practical applications. Herein, a low‐voltage and high‐performance photodetector based on a single layer of lead‐free Sn‐based perovskite film is reported. The device shows broadband response from ultraviolet to near‐infrared light with a responsivity up to 10
5
A W
−1
and a high gain at a low operating voltage. The outstanding performance is attributed to the high hole mobility, p‐doping nature, and excellent optoelectronic properties of the Sn‐based perovskite. Moreover, the device is assembled on a flexible substrate and demonstrates both high sensitivity and good bending stability. This work demonstrates a route for realizing nontoxic, low‐cost, and high‐performance perovskite photodetectors with a simple device structure.
“…Pristine FASnI 3 is unstable in air because Sn 2+ can be easily oxidized to Sn 4+ . [4][5][6][7] Thus, it is necessary to develop the next-generation PDs based on novel materials and designs. [32] The device based on the stable FASnI 3 layer displays high responsivity in a broad wavelength region from 300 to 1000 nm with the maximum responsivity and gain over 10 5 A W −1 and 10 5 , respectively, at a low working voltage.…”
Section: Doi: 101002/advs201900751mentioning
confidence: 99%
“…Photodetectors (PDs) have been widely used for various applications, such as optical communication, biomedical imaging, health care monitoring, video imaging, building inspection, and night vision . However, commercial III–V compound or Si‐based PDs normally suffer from relatively low response, high driving voltage, limited spectral response, and expensive fabrication . Thus, it is necessary to develop the next‐generation PDs based on novel materials and designs.…”
Organic–inorganic hybrid perovskites have emerged as promising functional materials for high‐performance photodetectors. However, the toxicity of Pb and the lack of internal gain mechanism in typical perovskites significantly hinder their practical applications. Herein, a low‐voltage and high‐performance photodetector based on a single layer of lead‐free Sn‐based perovskite film is reported. The device shows broadband response from ultraviolet to near‐infrared light with a responsivity up to 10
5
A W
−1
and a high gain at a low operating voltage. The outstanding performance is attributed to the high hole mobility, p‐doping nature, and excellent optoelectronic properties of the Sn‐based perovskite. Moreover, the device is assembled on a flexible substrate and demonstrates both high sensitivity and good bending stability. This work demonstrates a route for realizing nontoxic, low‐cost, and high‐performance perovskite photodetectors with a simple device structure.
“…The superlattice was designed using the empirical tight–binding model (ETBM) 25 . The photo−generated carrier transport inside the absorption region relies entirely on diffusion; thus, the new photo–generated carrier extractor does not require the applied bias which is required by other unipolar photodetector structures, such as nBn and pMp 17,26,27 ; as such, it functions under zero bias like a conventional pn junction photodetector.Figure 1Schematic diagram of conduction (E C ) and valence (E V ) bands of the visible/e–SWIR photodetector at 150K, with a bandstructure–engineered photo–generated carrier extractor. Section 1, 2, 3, 4, and 5 of the device have ~760, 580, 715, 1040, and 800 meV bandgap, respectively.…”
Visible/extended short–wavelength infrared photodetectors with a bandstructure–engineered photo–generated carrier extractor based on type–II InAs/AlSb/GaSb superlattices have been demonstrated. The photodetectors are designed to have a 100% cut-off wavelength of ~2.4 μm at 300K, with sensitivity down to visible wavelengths. The photodetectors exhibit room–temperature (300K) peak responsivity of 0.6 A/W at ~1.7 μm, corresponding to a quantum efficiency of 43% at zero bias under front–side illumination, without any anti–reflection coating where the visible cut−on wavelength of the devices is <0.5 µm. With a dark current density of 5.3 × 10−4 A/cm2 under −20 mV applied bias at 300K, the photodetectors exhibit a specific detectivity of 4.72 × 1010 cm·Hz1/2/W. At 150K, the photodetectors exhibit a dark current density of 1.8 × 10−10 A/cm2 and a quantum efficiency of 40%, resulting in a detectivity of 5.56 × 1013 cm·Hz1/2/W.
“…Recent advances in semiconductor materials and devices have led to much progress in the development of photodetectors for numerous applications across a variety of fields. Photodetectors are now able to broadly cover wavelengths from deep UV, visible, and near-infrared spectra all the way up to long-wavelength infrared (LWIR) and even terahertz spectral bands 1 – 8 . As the prospects for conventional pin detectors begin to saturate, there is a need to develop new designs, such as barrier photodetectors and ultra-sensitive devices with internal/intrinsic gain, that can yield better detectivity.…”
The LWIR and longer wavelength regions are of particular interest for new developments and new approaches to realizing long-wavelength infrared (LWIR) photodetectors with high detectivity and high responsivity. These photodetectors are highly desirable for applications such as infrared earth science and astronomy, remote sensing, optical communication, and thermal and medical imaging. Here, we report the design, growth, and characterization of a high-gain band-structure-engineered LWIR heterojunction phototransistor based on type-II superlattices. The 1/e cut-off wavelength of the device is 8.0 µm. At 77 K, unity optical gain occurs at a 90 mV applied bias with a dark current density of 3.2 × 10−7 A/cm2. The optical gain of the device at 77 K saturates at a value of 276 at an applied bias of 220 mV. This saturation corresponds to a responsivity of 1284 A/W and a specific detectivity of 2.34 × 1013 cm Hz1/2/W at a peak detection wavelength of ~6.8 µm. The type-II superlattice-based high-gain LWIR device shows the possibility of designing the high-performance gain-based LWIR photodetectors by implementing the band structure engineering approach.
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