Low-Noise Mid-Infrared Photodetection in BP/h-BN/Graphene van der Waals Heterojunctions

Quantum enhanced efficiency and spectral performance of paper-based flexible photodetectors functionalized with two dimensional materials

Flexible photodetectors (PDs) have exotic significance in recent years due to their enchanting potential in future optoelectronics. Moreover, paper-based fabricated PDs with outstanding flexibility unlock new avenues for future wearable electronics. Such PD has captured scientific interest for its efficient photoresponse properties due to the extraordinary assets like significant absorptive efficiency, surface morphology, material composition, affordability, bendability, and biodegradability. Quantum-confined materials harness the unique quantum-enhanced properties and hold immense promise for advancing both fundamental scientific understanding and practical implication. Two-dimensional (2D) materials as quantum materials have been one of the most extensively researched materials owing to their significant light absorption efficiency, increased carrier mobility, and tunable band gaps. In addition, 2D heterostructures can trap charge carriers at their interfaces, leading increase in photocurrent and photoconductivity. This review represents comprehensive discussion on recent developments in such PDs functionalized by 2D materials, highlighting charge transfer mechanism at their interface. This review thoroughly explains the mechanism behind the enhanced performance of quantum materials across a spectrum of figure of merits including external quantum efficiency, detectivity, spectral responsivity, optical gain, response time, and noise equivalent power. The present review studies the intricate mechanisms that reinforce these improvements, shedding light on the intricacies of quantum materials and their significant capabilities. Moreover, a detailed analysis of the technical applicability of paper-based PDs has been discussed with challenges and future trends, providing comprehensive insights into their practical usage in the field of future wearable and portable electronic technologies.

Study on Black Phosphorus Characteristics Using a Two-Step Thinning Method

A mild two-step method of black phosphorus (BP) flake thinning was demonstrated in this article. Slight ultraviolet-ozone (UVO) radiation followed by an argon plasma treatment was employed to oxidize mechanically exfoliated BP flakes and remove the surface remains of previous ozone treatment. The annealing process introduced aims to reduce impurities and defects. Low damage and efficient electronic devices were fabricated in terms of controlling the thickness of BP flakes through this method. These results lead to an important step toward the fabrication of high-performance devices based on two-dimensioned materials.

Chalcogenide-based, all-dielectric, ultrathin metamaterials with perfect, incidence-angle sensitive, mid-infrared absorption: inverse design, analysis, and applications

The demand for miniature, low-cost, utmost efficient optical absorbers triggered ongoing research efforts to minimize the overall design thickness, particularly the photo-active layer, while still maintaining a high optical absorptance. In this study, we present all-dielectric nanophotonic metamaterials of optimized, fabrication compatible and tolerant, architecture for perfect mid-wave infrared absorptance. Overall sub-vacuum-wavelength thick designs are intended to couple and confine light inside an ultrathin 100 nm PbTe photo-absorbing film. Three application-oriented structures, with dimensions inversely designed to provide diverse requirements, are introduced: a two-dimensional metasurface embedded design for unpolarised wide-band absorption and two, one-dimensional metasurface embedded designs for s-polarised wide-band and non-polarised narrow-band absorption. A comprehensive study of the structures' spectral absorptance under normal- and oblique-incidence irradiation is performed. The conical-mounting absorptance analysis elucidates that the high absorption can be continuously spectrally tuned with the azimuthal component of the incidence angle. To the best of our knowledge, this property is discussed for the first time for all-dielectric metamaterials. Also, the ranges of geometrical tuning of the peak absorptance are investigated in detail, and usage of another prospective semiconductor absorber is explored. To unfold the mutual, and essentially different, physical mechanisms that fuel the perfect absorptance, an elaborated analysis is presented. The electromagnetic power transport, portrayed by the Poynting vector, displays three-dimensional singular flows around points, such as vorticity centers, saddles, sinks, and spirals. The potential mid-infrared applications which can benefit from the peculiar properties of the designed structures, such as spectroscopy, sensing, thermal radiation manipulations, and communication, are also discussed.

MoS2/h-BN/Graphene Heterostructure and Plasmonic Effect for Self-Powering Photodetector: A Review

A photodetector converts optical signals to detectable electrical signals. Lately, self-powered photodetectors have been widely studied because of their advantages in device miniaturization and low power consumption, which make them preferable in various applications, especially those related to green technology and flexible electronics. Since self-powered photodetectors do not have an external power supply at zero bias, it is important to ensure that the built-in potential in the device produces a sufficiently thick depletion region that efficiently sweeps the carriers across the junction, resulting in detectable electrical signals even at very low-optical power signals. Therefore, two-dimensional (2D) materials are explored as an alternative to silicon-based active regions in the photodetector. In addition, plasmonic effects coupled with self-powered photodetectors will further enhance light absorption and scattering, which contribute to the improvement of the device's photocurrent generation. Hence, this review focuses on the employment of 2D materials such as graphene and molybdenum disulfide (MoS2) with the insertion of hexagonal boron nitride (h-BN) and plasmonic nanoparticles. All these approaches have shown performance improvement of photodetectors for self-powering applications. A comprehensive analysis encompassing 2D material characterization, theoretical and numerical modelling, device physics, fabrication and characterization of photodetectors with graphene/MoS2 and graphene/h-BN/MoS2 heterostructures with plasmonic effect is presented with potential leads to new research opportunities.

Electrophoretic Deposition of WS2 Flakes on Nanoholes Arrays-Role of Used Suspension Medium

Here we optimized the electrophoretic deposition process for the fabrication of WS₂ plasmonic nanohole integrated structures. We showed how the conditions used for site-selective deposition influenced the properties of the deposited flakes. In particular, we investigated the effect of different suspension buffers used during the deposition both in the efficiency of the process and in the stability of WS₂ flakes, which were deposited on an ordered arrays of plasmonic nanostructures. We observed that a proper buffer can significantly facilitate the deposition process, keeping the material stable with respect to oxidation and contamination. Moreover, the integrated plasmonic structures that can be prepared with this process can be applied to enhanced spectroscopies and for the preparation of 2D nanopores.