Black phosphorus (BP) is a promising two-dimensional layered semiconductor material for next-generation electronics and optoelectronics, with a thickness-dependent tunable direct bandgap and high carrier mobility. Though great research advantages have been achieved on BP, lateral synthesis of high quality BP films still remains a great challenge. Here, we report the direct growth of large-scale crystalline BP films on insulating silicon substrates by a gasphase growth strategy with an epitaxial nucleation design and a further lateral growth control. The optimized lateral size of the achieved BP films can reach up to millimeters, with the ability to modulate thickness from a few to hundreds of nanometers. The as-grown BP films exhibit excellent electrical properties, with a field-effect and Hall mobility of over 1200 cm 2 V −1 s −1 and 1400 cm 2 V −1 s −1 at room temperature, respectively, comparable to those exfoliated from BP bulk crystals. Our work opens the door for broad applications with BP in scalable electronic and optoelectronic devices.

Strong-field-enhanced spectroscopy in a hybrid dipole resonance system composed of a low-loss semiconductor nanoparticle and metal film is proposed and demonstrated. This hybrid Si nanoparticle on silver system is featuring extraordinary near-field enhancement and large field confinement. Extensive numerical calculations are carried out to investigate the influence of the gap size, particle diameter, and metal substrate on the near-field enhancement response in the Si particle–metal gap in order to properly model their hybridization. Our analysis reveals that this near-field enhancement originates from the strong gap magnetic resonance response by the Si nanoparticle dipole interaction with metal mirror image and metal film surface plasmon effects. We further demonstrate the strong enhanced Raman spectroscopy of a single silicon nanoparticle over Ag film with a precisely sized molecular spacer layer between them. These results illustrate the capacity and tunability of the low-loss silicon particle on the metal system on surface-enhanced spectroscopic techniques as well as possible applications in optical circuits or building new metamaterials.

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Aim Documenting the elevational species richness patterns of non‐volant small mammals and assessing the roles of pure spatial factors and spatial structured environmental factors in shaping the elevational richness patterns. Location Gyirong Valley in the Mount Qomolangma National Nature Reserve, located in the southern Himalayas, China. Methods Field surveys were conducted at each of twelve 300‐m elevational bands along a gradient from 1,800 to 5,400 m above sea level (a.s.l). For the pure spatial variables, we calculated area and the spatial null model named MDE (cf. below). For spatial structured environmental variables, we calculated mean annual temperature, mean annual precipitation, mean annual temperature range, potential evapotranspiration (PET), the normalized difference vegetation index, plant species richness and habitat heterogeneity. Multivariate models of species richness against eight factors (excluding PET) for different species groups were used to test the explanatory power of both the spatial structured environmental variables and the pure spatial variables. In addition, mean annual precipitation and potential evapotranspiration were used to test the water–energy dynamics model for each species groups. Results Seven hundred and fifty‐five individuals of 22 species were documented over 21,600 trap nights. The elevational species richness pattern for all non‐volant small mammals was hump‐shaped with the highest richness occurring at 2,700–3,300 m a.s.l. Endemic and non‐endemic species as well as two elevational range size categories of small mammals also generally showed hump‐shaped species richness patterns. In most data sets, spatial structured environmental variables played more important roles than the pure spatial variables in shaping the elevational species richness patterns than the pure spatial factors, while the MDE contributed to richness patterns for large‐ranged species. The water–energy dynamics model explained 66% of the variation in all the non‐volant small mammals, 56% for endemic species, 88% for the non‐endemic species, 59% for the large‐ranged species, and 53% for the small‐ranged species. Main conclusions Although no single key factor can explain all species richness patterns, we found that spatial structured environmental variables correlate well with the elevational species richness pattern of non‐volant small mammals. The water–energy dynamics model was found to explain non‐volant small mammal species richness along the Gyirong Valley.

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At present, most of the intelligent fault diagnosis methods of rolling element bearings require sufficient labeled data for training. However, collecting labeled data is usually expensive and timeconsuming, and when the distribution of the test data is different from the distribution of the training data, the diagnostic performance will decrease. In order to solve the problem of unlabeled cross-domain diagnosis of bearings, this paper proposes an adversarial domain adaption method based on deep transfer learning. The short-time Fourier transform is used to transform the original data into a time-frequency image. The feature extractor is used to extract its deep features. The maximum mean discrepancy and domain confusion function are used for domain adaptation to extract domain-invariant features between two domains for cross-domain fault diagnosis. Experiments on two bearing datasets are carried out for validations. The results prove that the method in this paper is superior to other deep transfer learning methods. It shows the advantages of the improved method and can be used as an effective tool for crossdomain fault diagnosis. INDEX TERMS Transfer learning, fault diagnosis, domain adaption, deep learning.

The compact and low-cost surface-emitting lasers in the 3−5 μm mid-infrared (MIR) range are highly desirable for important applications such as gas detection, noninvasive medical diagnosis, and infrared scene projection. Due to the intrinsic noise of general narrow-bandgap semiconductors, the MIR is a challenging region for photonics. Here, we demonstrate the first black phosphorus (BP)-based MIR surface-emitting laser operating at room temperature fabricated with BP as the active gain materials embedded into a SiO 2 /Si 3 N 4 open microcavity on silicon. Optically pumped lasing at ∼3765 nm is successfully realized in the demonstrated device by significantly increased luminescence efficiency in the BP lamellar structure and resolving the general issues for processing BP and other two-dimensional materials as gain medium with the specific design of an open cavity. This is the first demonstration of a BP-based light-emitting device and thus paves a pathway toward monolithic integration of Si-photonics in the MIR range.

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