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- 实验方案
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Ultra-broadband, sensitive and fast photodetection with needle-like EuBiSe3 single crystal
摘要： Ultra-broadband photodetection has been a hot topic with the rapid development of materials science and the application requirements for communication, imaging and sensing. Photodetectors based on bandgap-independent bolometry are promising candidates for detection of light from the ultraviolet to the terahertz range. Here we report a photothermoelectric detector made of an alloy of EuBiSe3 single crystal. The device shows room-temperature self-powered photoresponse from ultraviolet (375 nm) to terahertz (163 μm) with nearly uniform sensitivity against wavelength and fast response speed. Thanks to the large thermoelectric power (Seebeck coefficient) of EuBiSe3, the photovoltage responsivity derived from the incident (not absorbed) power reaches as high as 1.69 V/W at 405 nm without any bias voltage, and exceeds 0.59 V/W even at terahertz frequencies, with noise-equivalent power below 1 nW/√Hz, which is 1–2 orders of magnitude lower than reported photothermoelectric detectors. The response time is around 200 ms, nearly two orders of magnitude faster than silicon-based heterojunction ultra-broadband photodetectors and on the same order as the millimetric-scale graphene- and carbon nanotube-based bolometric photodetectors. In addition, the as-grown EuBiSe3 crystal possesses a unique needle-like shape, intrinsically facilitating integration of the detector. Our work demonstrates that improved thermoelectric materials hold great promise for room-temperature high-performance broadband photodetection.
关键词： EuBiSe3,photothermoelectric,ultra-broadband,sensitive,photodetector,self-powered
更新于2025-09-23 15:22:29
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Ultrasensitive Ambient-Stable SnSe<sub>2</sub>-based Broadband Photodetectors for Room-Temperature IR/THz Energy conversion and Imaging
摘要： The advent of tin diselenide (SnSe2) enables novel pathways for optoelectronics, due to its reduced cost, ultralow thermal conductivity and high potential for thermoelectricity. To date, SnSe2-based optoelectronic devices have been focused on the visible and infrared range of the electromagnetic spectrum, with efficiency sharply decreasing at longer wavelength. Here, we present SnSe2 photodetectors with exfoliated SnSe2 nanosheets extended in the range of THz frequency, exhibiting high responsivity (170 V W-1), fast speed(2.2 μs), as well as room-temperature operation, based on efficient production of hot electrons under deep-subwavelength electromagnetic focus, which outperform thermal-based photodetectors. The outstanding ambient stability of our broadband photodetectors in a timescale of months is due to the chemical inertness of stoichiometric SnSe2 crystals, validated by surface-science experiments. Our results demonstrate the suitability of SnSe2for multispectral sensing and real-time imaging. Our SnSe2-based detectors show high-contrast imaging from terahertz (THz) up to visible.
关键词： Photothermoelectric,Terahertz,Tin diselenide,Broadband photodetector
更新于2025-09-23 15:21:01
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Thermal Localization Enhanced Fast Photothermoelectric Response in a Quasi-one-dimensional Flexible NbS <sub/>3</sub> Photodetector
摘要： Ultra-broadband photodetection is crucial for various applications like imaging and sensing, and has become a hot research topic in recent years. However, most of the reported ultra-broadband photodetectors can only cover the range from ultraviolet to infrared, which is insufficient. Herein, a photothermoelectric (PTE) detector made of NbS3 is reported. The device shows a considerable performance from ultraviolet to terahertz. For all examined wavelengths, the photoresponsivities are all larger than 1 VW-1 while the response time is less than 10 ms, much shorter than the reported ultra-broadband photodetectors made of millimetric scale graphene, ternary chalcogenide single crystal and other materials. The extraordinary performance is fully discussed and can be attributed to the thermal localization enhanced PTE effect. Due to the short thermal decay length and low thermal loss, the heat generated by the illumination is localized in only a micrometer scale along the channel and thus a strong PTE response is produced. In addition, the fabricated device also demonstrates robust flexibility and stability. Thanks to the quasi-one-dimensional structure, the NbS3 crystal is easy to be scaled down and thus intrinsically facilitate the integration of detectors. With these favorable merits, the quasi-one-dimensional NbS3 crystal holds promising potential in high-performance, ultra-broadband photodectors.
关键词： photodetection,photothermoelectric effect,ultra-broadband,thermal localization,NbS3
更新于2025-09-19 17:13:59
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Progress of Photodetectors Based on the Photothermoelectric Effect
摘要： High-performance uncooled photodetectors operating in the long-wavelength infrared and terahertz regimes are highly demanded in the military and civilian fields. Photothermoelectric (PTE) detectors, which combine photothermal and thermoelectric conversion processes, can realize ultra-broadband photodetection without the requirement of a cooling unit and external bias. In the last few decades, the responsivity and speed of PTE-based photodetectors have made impressive progress with the discovery of novel thermoelectric materials and the development of nanophotonics. In particular, by introducing hot-carrier transport into low-dimensional material–based PTE detectors, the response time has been successfully pushed down to the picosecond level. Furthermore, with the assistance of surface plasmon, antenna, and phonon absorption, the responsivity of PTE detectors can be significantly enhanced. Beyond the photodetection, PTE effect can also be utilized to probe exotic physical phenomena in spintronics and valleytronics. Herein, recent advances in PTE detectors are summarized, and some potential strategies to further improve the performance are proposed.
关键词： thermoelectrics,low-dimensional materials,photothermoelectric effect,photodetectors,nanophotonics
更新于2025-09-19 17:13:59
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Plasmon induced thermoelectric effect in graphene
摘要： Graphene has emerged as a promising material for optoelectronics due to its potential for ultrafast and broad-band photodetection. The photoresponse of graphene junctions is characterized by two competing photocurrent generation mechanisms: a conventional photovoltaic effect and a more dominant hot-carrier-assisted photothermoelectric (PTE) effect. The PTE effect is understood to rely on variations in the Seebeck coefficient through the graphene doping profile. A second PTE effect can occur across a homogeneous graphene channel in the presence of an electronic temperature gradient. Here, we study the latter effect facilitated by strongly localised plasmonic heating of graphene carriers in the presence of nanostructured electrical contacts resulting in electronic temperatures of the order of 2000 K. At certain conditions, the plasmon-induced PTE photocurrent contribution can be isolated. In this regime, the device effectively operates as a sensitive electronic thermometer and as such represents an enabling technology for development of hot carrier based plasmonic devices.
关键词： Photothermoelectric effect,Graphene,Plasmonics,Photodetectors,Hot carriers
更新于2025-09-10 09:29:36