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Two‐dimensional (2D) transition‐metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) have recently attracted extensive interest for building future optoelectronic devices. However, the limited light absorption, low photoresponsivity and slow response speed in visible range inhibit their further application. Here, we proposed a promising approach to realize the high‐performance photodetectors (PDs) by constructing 2D‐MoS2 flake/1D‐ZnO nanowire mixed‐dimensional heterostructures. The integration of 1D‐ZnO on p‐type or n‐type MoS2 to form the mixed‐dimensional 2D‐MoS2/1D‐ZnO heterostructure PDs not only broadens the light response range, but also improves the photoresponsivity and response time of 2D‐MoS2 flakes. Under the 365 nm light illumination, the photoresponsivity, external quantum efficiency and response time of p‐MoS2/n‐ZnO PDs are as high as 24.36 A/W, 8.28×103 % and 0.9 s, respectively. Under 532 nm light illumination, the photoresponsivity, external quantum efficiency and response time are estimated to be 0.35 A/W, 80.9 % and 140 ms, respectively. These properties are superior or comparable to the performance of other reported 2D‐MoS2 flake PDs. This work provides a possible strategy for the realization of high‐performance optoelectronic devices by the integration of 2D‐MoS2 and 1D‐ZnO to form mixed‐dimensional heterostructures. [ABSTRACT FROM AUTHOR]

Photodetectors: Enhanced Performances of PVK/ZnO Nanorods/Graphene Heterostructure UV Photodetector via Piezo-Phototronic Interface Engineering (Adv. A sandwich heterostructure made of PVK/ZnO nanorods/graphene is designed for building ultraviolet photodetector. Graphene, heterojunction, photodetectors, piezo-phototronic effect, ZnO nanorods. [Extracted from the article]

The piezo‐phototronic effect can effectively engineer the energy band structure at the local interface of piezo‐semiconductor junction, and thus improve the performance of optoelectronics. In this work, a high‐performance poly(9‐vinylcarbazole) (PVK)/ZnO nanorods/graphene heterostructure photodetector is designed and fabricated using a multi‐step process. By introducing a −1.093% compressive strain to the hybrid heterostructure, carrier‐dynamics modulation at the local junctions can be induced by the piezoelectric polarization, and the photoresponsivity and the specific detectivity of the photodetector can be enhanced ≈440% and ≈132% under UV light illumination with the peak values up to 80.6 A W−1 and 2.3 × 1011 Jones, respectively. The photoresponse enhancement is attributed to the piezopotential generated at PVK/ZnO and ZnO/graphene interfaces, which promote the separation and transfer of photogenerated carriers. Physical working mechanism behind the observed results is discussed via energy band diagram. This work not only presents a new way to achieve the higher performance in photodetectors by fully utilizing piezo‐phototronic interface engineering but also provides a deep understanding of piezo‐phototronic effect on optoelectronic devices. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga 2 O 3) has attracted much attention for its ultra-wide band gap and superior optoelectronic properties in the field of ultraviolet (UV) photodetectors. However, Ga 2 O 3 -based photodetectors still face problems such as slow response speed, large dark current and high power consumption. In this work, we design an n-Ga 2 O 3 /p-GaN vertical heterojunction in a transverse device and use it to construct a high-performance UV photodetector. The GaN film directly connects to the electrodes, while the Ga 2 O 3 nanowires cover the top surface of the GaN and do not contact with any electrode. Based on this unique heterostructure, the photodetector demonstrates a low dark current and fast photoresponse speed under 254 nm irradiation. On the other hand, the photodetector can be operated at 0 V bias due to asymmetric Schottky barriers caused by the difference in electrode size. The photoresponse, specific detectivity and photoresponse speed of the photodetector are calculated to be 44.98 mA/W, 5.33 × 1011 Jones and 383 ms, respectively, under self-powered mode. The enhanced UV photoresponse and self-powered mechanism of the photodetector are discussed in detail via the schematic diagrams of energy band structure and carrier transport process. At last, a vivid image is obtained using the Ga 2 O 3 /GaN photodetector as an imaging pixel in the imaging system. This work provides an effective strategy to construct high-performance UV photodetectors toward optical imaging. [Display omitted] • A Ga 2 O 3 /GaN vertical heterostructure in a transverse photodetector is constructed. • The photodetector shows a fast photoresponse speed and high photoresponsivity. • The photodetector can be operated at 0 V bias due to asymmetric Schottky barrier height. • The enhanced UV photoresponse and self-powered mechanism of the photodetector are discussed in detail. • A vivid image is obtained using the Ga 2 O 3 /GaN photodetector as an imaging pixel in the imaging system. [ABSTRACT FROM AUTHOR]

(GaN) 1-x (ZnO) x solid solution (SS) attracts much attention in the field of photodetectors and photocatalysis due to their excellent photoresponse and adjustable band gap. Although (GaN) 1-x (ZnO) x nanoparticles, nanorods and nanosheets have been successfully synthesized, the preparation of one-dimensional (GaN) 1-x (ZnO) x SS nanobelts (SSNBs) and their photoresponse performance are rarely reported due to the difficulty of preparation. In this study, single crystal (GaN) 1-x (ZnO) x SSNBs with a ZnO content of ∼12.6% are synthesized by a convenient CVD method using liquid Ga as the nucleation site. The prepared NBs are pure (GaN) 1-x (ZnO) x SS and not the two-phase compound of ZnO and GaN. More important, the SSNBs with tens of micrometers in length and hundreds of nanometers in width feature the excellent ultraviolet and visible light response. Upon UV illumination (365 nm), the photodetector based on a single (GaN) 1-x (ZnO) x SSNB achieves a photoresponse speed of 330 ms and a photoresponsivity of 2.8 × 105 A/W. Under visible illumination (532 nm), the photodetector displays a photoresponse speed of 480 ms and a photoresponse of 1.9 × 104 A/W. This study not only proposes a new method for the synthesis of (GaN) 1-x (ZnO) x SSNBs, but also paves the way for the use of (GaN) 1-x (ZnO) x SSNBs as building blocks for broad-spectrum responsive photodetectors. [Display omitted] • Pure-phase (GaN) 1-x (ZnO) x solid solution nanobelts are synthesized by CVD method for the first time. • The high-responsivity photodetector based on an individual (GaN) 1-x (ZnO) x nanobelt is fabricated. • The photodetector enables a wide range of detection from UV to visible light. • The photoresponsivity is as high as 2.8 × 105 A/W and the photoresponse speed is as fast as 330 ms. [ABSTRACT FROM AUTHOR]

Localized surface plasmon resonance (LSPR) as a unique property of metal nanoparticles (NPs) has been widely applied to enhance the performance of optoelectronic devices. However, limited by the specific resonance frequency of plasmonic NPs, the LSPR of NPs can only improve the photoresponse performance of photodetectors at specific wavelength. In this work, a simple strategy is proposed to simultaneously improve the performance of the p-MoS 2 /n-ZnO heterostructure photodetector in visible and ultraviolet (UV) light regions by modifying Au NPs. The I light /I dark ratio of the photodetector is considerably increased after the functionalization with plasmonic Au NPs under visible and UV light illumination due to the direct resonant coupling of LSPR. In particular, the photocurrent of the photodetector increases 14.8 times after Au NPs modification under 532 nm illumination, giving rise to an obvious increase in responsivity, external quantum efficiency and specific detectivity. Moreover, the modification of Au NPs facilitates the rapid separation of electrons and holes due to the generation of surface depletion regions located at Au/MoS 2 and Au/ZnO interfaces. Consequently, the photoresponse speed is also drastically improved after Au NPs decoration in both visible and ultraviolet light regions. The strategy of direct resonant coupling of Au NPs LSPR with two photosensitive materials proposed in this work will provide a new avenue for optimizing the performance of optoelectronic devices. [Display omitted] • Au nanoparticles modified p-MoS 2 /n-ZnO heterostructure photodetector is constructed. • The direct resonant coupling of Au nanoparticles LSPR leads to improved performance. • The photoresponsivity and response speed of the photodetector are enhanced in visible and UV light regions. • This work provides a new avenue for optimizing the performance of optoelectronic devices. [ABSTRACT FROM AUTHOR]