Semimetallic Graphene for Infrared Sensing

Abstract

Both photothermal and photovoltaic infrared (IR) detectors employ sensing materials that have an optical band gap. Different from these conventional materials, graphene has a conical band structure that imposes zero band gap. In this study, using the semimetallic multilayer graphene, IR detection at room temperature is realized. The relatively high Seebeck coefficient, ranging from 40 to 60 μV/K, compared to that of the metal, and the large optical absorption in the mid-IR region, in the wavelength range of 7–17 μm, enable graphene to detect IR without an absorber, which is essential for most IR detectors because the band gap of the sensing materials is much larger than the energy of IR and the incident IR can be absorbed directly by the sensing material. Thus, the incident IR can be absorbed directly by the sensing material in our device. The developed detector with a SiN membrane shows high responsivity and detectivity, which are 140 V/W and 5 × 108 cm·Hz1/2/W at 5 Hz, respectively. In addition, the IR sensor shows a response time of 600 μs. In the room-temperature operation of the IR sensor array without cooling, our sensors detect IR emitted from a human body and track the movement. The availability of large-area graphene in current technology opens new applications for metallic two-dimensional materials and a possibility for scale-up.

Transparent Patternable Large-Area Graphene p–n Junctions by Photoinduced Electron Doping

“…Graphene has garnered significant research interest owing to its exceptional properties, such as high charge carrier mobility , and excellent thermal conductivity, making it suitable for a wide range of applications, including flexible transparent electrodes, sensors, , thermoelectrics, and optoelectronic devices. , The challenging discrimination between coexisting p-type (positive charge carriers or “holes”) and n-type (negative charge carriers or “electrons”) doping in graphene hinders the development of practical applications in graphene-based devices. Although p-type doping in graphene has been achievable, stable and highly efficient n-type doping remains significantly challenging .…”

High‐Performance Photodetector Based on Bi2Se3/GeSe Heterojunction with Band Alignment Evolution

“…[4,9,10] Among them, photodetectors constructed using narrow bandgap 2D materials have been widely studied in the field of broadband photoelectric detection from ultraviolet to terahertz bands. [11][12][13][14] Meanwhile, polarized photodetection, as another important factor of photodetection, can effectively reduce the bit error rate by combining the scattering, transmission, and reflection information of objects in complex environments. [15][16][17][18][19] With the continuous improvement of detection accuracy and miniaturization requirements, the introduction of 2D polarization materials with ultra-high carrier mobility, adjustable bandgap, and intrinsic anisotropy has become a new research hotspot in the field of polarization detection and imaging.…”

Stability and Bandgap Engineering of In1−xGaxSe Monolayer

“…They offer the opportunity of creating vertical heterostructures without the "lattice mismatch" issue, because of weak interactions between different monolayers (van der Waals forces). In addition, most 2D structures interact strongly with light and can be used to cover a wide electromagnetic spectrum thanks to their diverse electronic properties, ranging from insulating hexagonal boron nitride (hBN) [8,12] and semiconducting transition metal dichalcogenides (TMDs) [13,14] to semimetallic graphene [15].…”