Broadband Room-Temperature Photodetection via InBiTe3 Nanosheet.

Broadband room-temperature photodetection has become a pressing need as application requirements for communication, imaging, spectroscopy, and sensing have evolved. Topological insulators (TIs) have narrow bandgap structures with a wide absorption spectral response range, which should meet the requirements of broadband detection. However, owing to their high carrier concentration and low carrier mobility resulting in poor noise equivalent power (NEP), they are generally considered unsuitable for photodetection. Here, InBiTe3 alloy nanosheet formed by doping In2Te3 into Bi2Te3(≈ 1:1) is utilized, effectively improving carrier mobility by over ten times while maintaining a narrow bandgap structure, to fabricate a broadband photodetector covering a wide response range from visible to millimeter wave (MMW). Under the synergistic multi-mechanism of the photoelectric effect in the visible-infrared region and the electromagnetic-induced potential well (EIW) effect in Terahertz band, the performance of NEP = 75 pW Hz-1/2 and response time τ ≈100 µs in visible to infrared band and the performance of NEP = 6.7 × 10-3 pW Hz-1/2, τ ≈8 µs in Terahertz region are achieved. The results demonstrate the promising prospects of topological insulator alloy (like InBiTe3) nanosheet in optoelectronic detection applications and provide a direction for the research into high-performance broadband photoelectric detectors via TIs.

High sensitivity of room-temperature terahertz photodetector based on silicon.

Silicon (Si) is the most important semiconductor material broadly used in both electronics and optoelectronics. However, the performance of Si-based room temperature detectors is far below the requirements for direct detection in the terahertz (THz) band, a very promising electromagnetic band for the next-generation technology. Here, we report a high sensitivity of room temperature THz photodetector utilizing the electromagnetic induced well mechanism with an SOI-based structure for easy integration. The detector achieves a responsivity of 122 kV W-1, noise equivalent power (NEP) of 0.16 pW Hz-1/2, and a fast response of 1.29 µs at room temperature. The acquired NEP of the detector is âˆ¼2 orders lower in magnitude than that of other types of Si-based detectors. Our results pave the way to realize Si-based THz focal plane arrays, which can be used in a wide range of applications, such as medical diagnosis, remote sensing, and security inspection.

High Performance of Room-Temperature NbSe2 Terahertz Photoelectric Detector.

Photoelectric detection is developing rapidly from ultraviolet to infrared band. However, terahertz (THz) photodetection approaches is constrained by the bandgap, dark current, and absorption ability. In this work, room-temperature photoelectric detection is extended to the THz range implemented in a planar metal-NbSe2-metal structure based on an electromagnetic induced well (EIW) theory, exhibiting an excellent broadband responsivity of 5.2 × 107 V W-1 at 0.027 THz, 7.8 × 106 V W-1 at 0.173 THz, and 9.6 × 105 V W-1 at 0.259 THz. Simultaneously, the NbSe2 photoelectric detector (PD) with ultrafast response speed (∼610 ns) and ultralow equivalent noise power (4.6 × 10-14 W Hz-1/2) in the THz region is realized, enabling high-resolution imaging. The figure of merit (FOM) characterizing the detection performance of the device is 2 orders of magnitude superior to that of the reported THz PDs based 2D materials. Furthermore, the THz response speed is 2 orders of magnitude faster than that of the visible due to the different response mechanisms of the device. Our results exhibit promising potential to achieve highly sensitive and ultrafast photoelectric detection.

Ultrabroadband Tellurium Photoelectric Detector from Visible to Millimeter Wave.

Ultrabroadband photodetection is of great significance in numerous cutting-edge technologies including imaging, communications, and medicine. However, since photon detectors are selective in wavelength and thermal detectors are slow in response, developing high performance and ultrabroadband photodetectors is extremely difficult. Herein, one demonstrates an ultrabroadband photoelectric detector covering visible, infrared, terahertz, and millimeter wave simultaneously based on single metal-Te-metal structure. Through the two kinds of photoelectric effect synergy of photoexcited electron-hole pairs and electromagnetic induced well effect, the detector achieves the responsivities of 0.793 A W-1 at 635 nm, 9.38 A W-1 at 1550 nm, 9.83 A W-1 at 0.305 THz, 24.8 A W-1 at 0.250 THz, 87.8 A W-1 at 0.172 THz, and 986 A W-1 at 0.022 THz, respectively. It also exhibits excellent polarization detection with a dichroic ratio of 468. The excellent performance of the detector is further verified by high-resolution imaging experiments. Finally, the high stability of the detector is tested by long-term deposition in air and high-temperature aging. The strategy provides a recipe to achieve ultrabroadband photodetection with high sensitivity and fast response utilizing full photoelectric effect.

High Order Magnetic and Electric Resonant Modes of Split Ring Resonator Metasurface Arrays for Strong Enhancement of Mid-Infrared Photodetection.

Integration of photonic nanostructures with optoelectrical semiconductors offers great potential of developing high sensitivity and multifunctional photodetectors enabled by enhanced light-matter interactions. Split ring resonator (SRR) array which resonates at different resonant modes, including fundamental magnetic mode (m0), high order magnetic mode (m1), and electric (e) mode has been investigated because of the high potential for different applications. In this work, we study photodetection enhancement of these resonant modes of U-shape SRR arrays in the mid-infrared (2-5 µm) range and report, for the first time, the strong enhancement of photodetection by superimposition of m1 and e modes in an integrated photodetector consisting of a U-shape SRR array and an InAsSb-based heterojunction photodiode. We observe that the m1 mode in the SRR array shows the strongest enhancement of photocurrent, sequentially followed by the e and m0 modes. Using superimposed m1 and e modes, about an order of enhancement in room temperature detectivity (to about 2.0 × 1010 Jones) is achieved under zero-power-supply without sacrificing the response speed. In addition, polarization-resolved photoresponse between m1 and e modes and tunable enhancement of photoresponse are also demonstrated. The remarkable enhancement makes mid-infrared photodetection possible to operate at room temperature.

Indium antimonide uncooled photodetector with dual band photoresponse in the infrared and millimeter wave range.

All-InSb film-based and spiral antenna-assisted Au-InSb-Au metal-semiconductor-metal detector is reported with dual-band photoresponse in the infrared (IR) and millimeter wave range. At IR, the detector exhibits a long wavelength 100% cut-off at 7.3 µm. Under an applied bias of 5 mA, the uncooled blackbody responsivity and specific detectivity are 3.5 A/W and 1×108 Jones, respectively. The f-3dB value measured at 2.94 µm is 75 KHz, corresponding to a detector rise speed of 4.7 µs. At millimeter wave range, the detector shows a narrowband response determined by the coupling of the antenna. A voltage responsivity of 25 V/W is achieved at 167 GHz (1.796 mm) under an applied bias of 25 mA, and the corresponding noise equivalent power (NEP) is 1.0×10-10 WHz-1/2, which can be improved to 1.8×10-12 WHz-1/2 if normalized to the real active semiconductor area. A f-3dB value of 17.5 KHz, corresponding to a detector rise speed of 20 µs is achieved in this range. A proof of principle for IR-modulated photoresponse for millimeter wave is achieved with a maximum modulation depth of 47.5%. This All-InSb film-based detector and the modulation are promising for future novel optoelectronic devices in IR and millimeter waves.

Broadband infrared thermal detection using manganese cobalt nickel oxide thin film.

Room temperature, broadband infrared (IR) bolometer was investigated for the first time by using Mn1.56Co0.96Ni0.48O4 (MCNO) thin film with dielectric-metal-dielectric absorptive layers. The Si3N4/NiCr/SiO2 layer was constructed to improve light absorption. A responsivity of 98.6 V/W and D* of 2.1 × 107 cm∙Hz0.5/W@20 Hz, with a typical time constant of 14.5 ms, was obtained with a 1550 nm laser. The response spectra of the detector covered the range from near to far infrared, which greatly enhanced the potential of MCNO films in large-scale IR thermal detection applications. This study provides an efficient way to develop large scale, broadband MCNO IR detectors.