Bing Wang

Bio: Bing Wang is an academic researcher from Shenzhen University. The author has contributed to research in topics: Responsivity & Photodetector. The author has an hindex of 6, co-authored 7 publications receiving 179 citations.

Self-Assembly High-Performance UV-vis-NIR Broadband β-In2Se3/Si Photodetector Array for Weak Signal Detection.

Abstract: The emergence of a rich variety of layered materials has attracted considerable attention in recent years because of their exciting properties. However, the applications of layered materials in optoelectronic devices are hampered by the low light absorption of monolayers/few layers, the lack of p–n junction, and the challenges for large-scale production. Here, we report a scalable production of β-In2Se3/Si heterojunction arrays using pulsed-laser deposition. Photodetectors based on the as-produced heterojunction array are sensitive to a broadband wavelength from ultraviolet (370 nm) to near-infrared (808 nm), showing a high responsivity (5.9 A/W), a decent current on/off ratio (∼600), and a superior detectivity (4.9 × 1012 jones), simultaneously. These figures-of-merits are among the best values of the reported heterojunction-based photodetectors. In addition, these devices can further enable the detection of weak signals, as successfully demonstrated with weak light sources including a flashlight, lighte...

Tin dioxide quantum dots coupled with graphene for high-performance bulk-silicon Schottky photodetector

Abstract: Commercial photodetectors have been dominated by bulk silicon (B-Si) due to the maturity of Si technology. However, its relatively poor mobility has impeded B-Si from high-performance applications. Herein, we demonstrate that tin dioxide quantum dots (SnO2-QDs) coupled with graphene produce a Schottky junction with B-Si to drastically promote the performance of the SnO2-QDs/graphene/B-Si Schottky photodetector. This hybrid device is sensitive to broadband illumination covering the UV-vis-NIR region and shows high responsivity of 967.6 A W−1 (nearly 4 orders higher than that of commercial B-Si Schottky photodetectors), with corresponding external quantum efficiency of 2.3 × 105% and detectivity of 1.8 × 1013 Jones. In addition, the hybrid device manifests fast rise and decay times of 0.1 and 0.23 ms, respectively. These figures-of-merit are among the best values of the recently reported B-Si Schottky photodetectors. We also established that the superior performances are attributed to the strong light absorption of the hybrid structure and increased built-in potential of the graphene/B-Si Schottky junction, which allows efficient separation of photoexcited electron–hole pairs. These findings pave the way toward the rational design of optoelectronic devices through the synergetic effects of 2D materials with 0D and 3D semiconductors.

Present advances and perspectives of broadband photo-detectors based on emerging 2D-Xenes beyond graphene

Abstract: As an excellent optical device, photodetectors have many important applications, such as communication technology, display technology, scientific measurement, fire monitoring, aerospace and biomedical research, and it’s of great significance in the research of nanotechnology and optoelectronics. Graphene, as the first two-dimensional (2D) single-element nanomaterial, has the advantages of high carrier mobility, high strength, high light transmittance and excellent thermal conductivity, and it’s widely used in various nano-optical devices. The great success of graphene has led scientists to extensive research on other 2D single-element nanomaterials. Recently, a group of novel 2D single-element nanomaterials have attracted a lot of attention from scientists because of its excellent physical, chemical, electronic, mechanical and optical properties. Furthermore, it has opened a new door for the realization of new and efficient photodetectors. The group of 2D single-element nanomaterials are called 2D-Xenes and used to make high-performance photodetectors. Currently, there are few studies on photodetectors based on 2D-Xenes, but some 2D-Xenes have been applied to photodetectors and reported. Some of these have excellent photodetection performance, such as high photoresponsivity (R), broad spectral response range, fast photoresponse speed and high specific detectivity (D*). Based on the novel 2D-Xenes, this review explores the types and preparation methods of 2D-Xenes, and the working mechanisms of 2D-Xenes photodetectors. Finally, the challenges and development trends of 2D-Xenes in the future are discussed. The research of 2D-Xenes is of great significance for the development of high-performance photodetectors in the future, and is expected to be widely used in other nanoelectronics and optical devices.

Epitaxial growth of large-scale In2S3 nanoflakes and the construction of a high performance In2S3/Si photodetector

Abstract: MoS2-like layered 2D materials have attracted attention worldwide due to their intriguing material properties. In contrast, it is still a great challenge to prepare non-layered 2D materials that may provide unique electronic and optoelectronic properties compared to layered materials. As an emerging IIIA–VIA semiconductor, In2S3 shows great potential for application in optoelectronics. Herein, ultrathin non-layered In2S3 nanoflakes, with uniform thickness and lateral size reaching the sub-millimeter scale, are synthesized on mica substrates via a simple physical vapor epitaxy method. Then, a photodetector based on an In2S3/Si heterojunction is fabricated. Owing to the strong light–matter interactions of In2S3 and the built-in potential at the In2S3/Si interface, which accelerates the separation of photoexcited electron–hole pairs, the device exhibits a broadband sensitivity covering the visible to near-infrared region. The responsivity, detectivity and rise/decay time are 579.6 A W−1, 2 × 1011 Jones and 9/0.131 ms, respectively. These performance metrics are among the best values when compared with those of reported layered 2D materials/Si heterojunction photodetectors. Notably, the In2S3/Si photodetector suffers from negligible performance degradation even after 1050 cycles of operation or 6 months of exposure to air. These findings broaden the scope of 2D materials and highlight that In2S3 nanoflakes hold great potential for further optoelectronic applications.

A flexible, transparent and high-performance gas sensor based on layer-materials for wearable technology

Abstract: Gas sensors play a vital role among a wide range of practical applications. Recently, propelled by the development of layered materials, gas sensors have gained much progress. However, the high operation temperature has restricted their further application. Herein, via a facile pulsed laser deposition (PLD) method, we demonstrate a flexible, transparent and high-performance gas sensor made of highly-crystalline indium selenide (In2Se3) film. Under UV-vis-NIR light or even solar energy activation, the constructed gas sensors exhibit superior properties for detecting acetylene (C2H2) gas at room temperature. We attribute these properties to the photo-induced charger transfer mechanism upon C2H2 molecule adsorption. Moreover, no apparent degradation in the device properties is observed even after 100 bending cycles. In addition, we can also fabricate this device on rigid substrates, which is also capable to detect gas molecules at room temperature. These results unambiguously distinguish In2Se3 as a new candidate for future application in monitoring C2H2 gas at room temperature and open up new opportunities for developing next generation full-spectrum activated gas sensors.

Synthesis of WS2xSe2-2x alloy nanosheets with composition-tunable electronic properties

Abstract: Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have recently emerged as a new class of atomically thin semiconductors for diverse electronic, optoelectronic, and valleytronic applications. To explore the full potential of these 2D semiconductors requires a precise control of their band gap and electronic properties, which represents a significant challenge in 2D material systems. Here we demonstrate a systematic control of the electronic properties of 2D-TMDs by creating mixed alloys of the intrinsically p-type WSe2 and intrinsically n-type WS2 with variable alloy compositions. We show that a series of WS2xSe2-2x alloy nanosheets can be synthesized with fully tunable chemical compositions and optical properties. Electrical transport studies using back-gated field effect transistors demonstrate that charge carrier types and threshold voltages of the alloy nanosheet transistors can be systematically tuned by adjusting the alloy composition. A highly p-type behavior is observed in selenium-rich alloy, which gradually shifts to lightly p-type, and then switches to lightly n-type characteristics with the increasing sulfur atomic ratio, and eventually evolves into highly n-doped semiconductors in sulfur-rich alloys. The synthesis of WS2xSe2-2x nanosheets with tunable optical and electronic properties represents a critical step toward rational design of 2D electronics with tailored spectral responses and device characteristics. © 2015 American Chemical Society.

Black Phosphorus Field-effect Transistors

Abstract: Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10(5) and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to ∼ 1,000 cm(2) V(-1) s(-1) obtained for a thickness of ∼ 10 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.

2D material broadband photodetectors

Abstract: Our review provides a comprehensive overview of the latest evolution of broadband photodetectors (BBPDs) based on 2D materials (2DMs). We begin with BBPDs built on various 2DM channels, including narrow-bandgap 2DMs, 2D topological semimetals, 2D charge density wave compounds, and 2D heterojunctions. Then, we introduce defect-engineered 2DM BBPDs, including vacancy engineering, heteroatom incorporation, and interfacial engineering. Subsequently, we summarize 2DM based mixed-dimensional (0D-2D, 1D-2D, 2D-3D, and 0D-2D-3D) BBPDs. Finally, we provide several viewpoints for the future development of this burgeoning field.