Switch type PANI/ZnO core-shell microwire heterojunction for UV photodetection
TL;DR: In this paper, single crystal ZnO microwires (MW) with size of ∼5.4 mm were prepared through a chemical vapor deposition technique at high temperature (1200 °C), and p-type conducting polyaniline (PANI) polymers with different conductivities were densely coated on part of the MW to construct organic/inorganic core-shell heterojunction photodetectors.
About: This article is published in Journal of Materials Science & Technology.The article was published on 2022-04-10. It has received 164 citations till now. The article focuses on the topics: Materials science & Responsivity.
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TL;DR: In this article , an in-depth illustration of the electrical and optical properties of TiO2 nanostructures in addition to the advances in the technological issues such as preparation, microdefects, p-type doping, bandgap engineering, heterojunctions, and functional applications are presented.
Abstract: As a wide‐bandgap semiconductor material, titanium dioxide (TiO2), which possesses three crystal polymorphs (i.e., rutile, anatase, and brookite), has gained tremendous attention as a cutting‐edge material for application in the environment and energy fields. Based on the strong attractiveness from its advantages such as high stability, excellent photoelectric properties, and low‐cost fabrication, the construction of high‐performance photodetectors (PDs) based on TiO2 nanostructures is being extensively developed. An elaborate microtopography and device configuration is the most widely used strategy to achieve efficient TiO2‐based PDs with high photoelectric performances; however, a deep understanding of all the key parameters that influence the behavior of photon‐generated carriers, is also highly required to achieve improved photoelectric performances, as well as their ultimate functional applications. Herein, an in‐depth illustration of the electrical and optical properties of TiO2 nanostructures in addition to the advances in the technological issues such as preparation, microdefects, p‐type doping, bandgap engineering, heterojunctions, and functional applications are presented. Finally, a future outlook for TiO2‐based PDs, particularly that of further functional applications is provided. This work will systematically illustrate the fundamentals of TiO2 and shed light on the preparation of more efficient TiO2 nanostructures and heterojunctions for future photoelectric applications.
111 citations
TL;DR: In this paper , a general strategy has been proposed for high-performance photodetectors through building a type-Ⅱ Ga2O3 heterojunction with the small-molecule hole transport materials (SMHTMs).
72 citations
TL;DR: In this article , surface modification with LiF, Se, and polyethylenimine ethoxylated (PEIE) electrodes was used to tune the window of MXene's work function.
Abstract: Tunable work function has a high profile for the MXene‐based optoelectronic devices, and surface modification provides the huge potential to shift its Fermi level and modulate the work function. In this work, the window of MXene's work function is engineered from 4.55 to 5.25 eV by surface modification with LiF, Se, and polyethylenimine ethoxylated (PEIE). The vertical p‐CsCu2I3/n‐Ca2Nb3‐xTaxO10 junction photodetectors are constructed on the basis of the above surface‐modified MXenes, which changes the Schottky barrier between n‐Ca2Nb3‐xTaxO10 and the electrodes. In particular, the rectification effect is significantly enhanced by utilizing PEIE‐decorated MXene electrodes, resulting in a high rectification ratio of 16 136 and improved UV responsivity of 81.3 A W–1. Such high‐performance devices based on MXenes electrodes are compatible with the standard clean room fabrication process, realizing large‐scale flexible UV detectors that maintain 80% of the original current after 5000 times bending. Meanwhile, a photodetector array stimulated with UV of different wavelengths is constructed to reveal its potential for image sensing. Finally, functional “AND” and “OR” optoelectronic logic gates are developed for UV communication using Au/CsCu2I3/Ca2Nb3‐xTaxO10/MXene–PEIE photodetectors, enriching the application of MXene‐based optoelectronic devices. This work on tuning MXene work function via surface modification demonstrates that MXene is a promising candidate for future optoelectronics.
40 citations
TL;DR: In this article , surface modification with LiF, Se, and polyethylenimine ethoxylated (PEIE) electrodes was used to tune the window of MXene's work function.
Abstract: Tunable work function has a high profile for the MXene-based optoelectronic devices, and surface modification provides the huge potential to shift its Fermi level and modulate the work function. In this work, the window of MXene's work function is engineered from 4.55 to 5.25 eV by surface modification with LiF, Se, and polyethylenimine ethoxylated (PEIE). The vertical p-CsCu2I3/n-Ca2Nb3-xTaxO10 junction photodetectors are constructed on the basis of the above surface-modified MXenes, which changes the Schottky barrier between n-Ca2Nb3-xTaxO10 and the electrodes. In particular, the rectification effect is significantly enhanced by utilizing PEIE-decorated MXene electrodes, resulting in a high rectification ratio of 16 136 and improved UV responsivity of 81.3 A W–1. Such high-performance devices based on MXenes electrodes are compatible with the standard clean room fabrication process, realizing large-scale flexible UV detectors that maintain 80% of the original current after 5000 times bending. Meanwhile, a photodetector array stimulated with UV of different wavelengths is constructed to reveal its potential for image sensing. Finally, functional “AND” and “OR” optoelectronic logic gates are developed for UV communication using Au/CsCu2I3/Ca2Nb3-xTaxO10/MXene–PEIE photodetectors, enriching the application of MXene-based optoelectronic devices. This work on tuning MXene work function via surface modification demonstrates that MXene is a promising candidate for future optoelectronics.
37 citations
TL;DR: In this article , a recent progress in 2D perovskite-based photodetectors is presented in detail, focusing on growth strategies for reducing thickness, thickness-dependent optical and electrical properties, device engineering, heterojunction fabrication, and device performance.
Abstract: Photodetectors are light sensors in widespread use in image sensing, optical communication, and consumer electronics. In current smart optoelectronic technology, conventional semiconductors have encountered a bottleneck caused by inflexibility and opacity. With the ever-increasing demands for versatile optoelectronic applications, perovskite-type 2D materials demonstrate great potential for advanced photodetectors inspired by molecularly thin 2D materials. Through the reduction of thickness to thin or molecularly thin levels, single-crystalline 2D perovskites can exhibit superior optoelectronic performance characteristics, such as tunable absorption property by chemical design, enhanced carrier separation by remarkable photosensing capability, and improved carrier extraction by versatile band engineering. More importantly, perovskite-type 2D materials exhibit great potential for large-scale monolithic integration to achieve all-in-one sensing-memory-computing optoelectronic devices. In this Perspective, recent progress in 2D perovskite-based photodetectors is presented in detail. The focus is on growth strategies for reducing thickness, thickness-dependent optical and electrical properties, device engineering, heterojunction fabrication, and device performance. Finally, the current challenges and future prospects in this field are presented.
36 citations
References
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14,205 citations
TL;DR: Despite the slow relaxation time, the extremely high internal gain of ZnO NW photodetectors results in gain-bandwidth products higher than approximately 10 GHz, which promise a new generation of phototransistors for applications such as sensing, imaging, and intrachip optical interconnects.
Abstract: ZnO nanowire (NW) visible-blind UV photodetectors with internal photoconductive gain as high as G ∼ 108 have been fabricated and characterized. The photoconduction mechanism in these devices has been elucidated by means of time-resolved measurements spanning a wide temporal domain, from 10-9 to 102 s, revealing the coexistence of fast (τ ∼ 20 ns) and slow (τ ∼ 10 s) components of the carrier relaxation dynamics. The extremely high photoconductive gain is attributed to the presence of oxygen-related hole-trap states at the NW surface, which prevents charge-carrier recombination and prolongs the photocarrier lifetime, as evidenced by the sensitivity of the photocurrrent to ambient conditions. Surprisingly, this mechanism appears to be effective even at the shortest time scale investigated of t < 1 ns. Despite the slow relaxation time, the extremely high internal gain of ZnO NW photodetectors results in gain-bandwidth products (GB) higher than ∼10 GHz. The high gain and low power consumption of NW photodetec...
2,448 citations
TL;DR: In this paper, the authors reported the observation of optically pumped lasing in ZnO at room temperature using a plasma-enhanced molecular beam epitaxy on sapphire substrates.
Abstract: We report the observation of optically pumped lasing in ZnO at room temperature. Thin films of ZnO were grown by plasma-enhanced molecular beam epitaxy on (0001) sapphire substrates. Laser cavities formed by cleaving were found to lase at a threshold excitation intensity of 240 kW cm−2. We believe these results demonstrate the high quality of ZnO epilayers grown by molecular beam epitaxy while clearly demonstrating the viability of ZnO based light emitting devices.
2,126 citations
TL;DR: An overview of the current state-of-the-art in silicon nanophotonic ring resonators is presented in this paper, where the basic theory of ring resonance is discussed and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes.
Abstract: An overview is presented of the current state-of-the-art in silicon nanophotonic ring resonators. Basic theory of ring resonators is discussed, and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes. Theory is compared to quantitative measurements. Finally, several of the more promising applications of silicon ring resonators are discussed: filters and optical delay lines, label-free biosensors, and active rings for efficient modulators and even light sources.
1,989 citations