Diamond is not only the hardest material in nature, but is also an extreme electronic material with an ultrawide bandgap, exceptional carrier mobilities, and thermal conductivity. Straining diamond ...can push such extreme figures of merit for device applications. We microfabricated single-crystalline diamond bridge structures with ~1 micrometer length by ~100 nanometer width and achieved sample-wide uniform elastic strains under uniaxial tensile loading along the 100, 101, and 111 directions at room temperature. We also demonstrated deep elastic straining of diamond microbridge arrays. The ultralarge, highly controllable elastic strains can fundamentally change the bulk band structures of diamond, including a substantial calculated bandgap reduction as much as ~2 electron volts. Our demonstration highlights the immense application potential of deep elastic strain engineering for photonics, electronics, and quantum information technologies.
Due to the enhanced ambient structural stability and excellent optoelectronic properties, all-inorganic metal halide perovskite nanowires have become one of the most attractive candidates for ...flexible electronics, photovoltaics and optoelectronics. Their elastic property and mechanical robustness become the key factors for device applications under realistic service conditions with various mechanical loadings. Here, we demonstrate that high tensile elastic strain (∼ 4% to ∼ 5.1%) can be achieved in vapor-liquid-solid-grown single-crystalline CsPbBr
3
nanowires through
in situ
scanning electron microscope (SEM) buckling experiments. Such high flexural elasticity can be attributed to the structural defect-scarce, smooth surface, single-crystallinity and nanomechanical size effect of CsPbBr
3
nanowires. The mechanical reliability of CsPbBr
3
nanowire-based flexible photodetectors was examined by cyclic bending tests, with no noticeable performance deterioration observed after 5,000 cycles. The above results suggest great application potential for using all-inorganic perovskite nanowires in flexible electronics and energy harvesting systems.
Abstract
Diamond, as an ultra-wide bandgap semiconductor, has become a promising candidate for next-generation microelectronics and optoelectronics due to its numerous advantages over conventional ...semiconductors, including ultrahigh carrier mobility and thermal conductivity, low thermal expansion coefficient, and ultra-high breakdown voltage, etc. Despite these extraordinary properties, diamond also faces various challenges before being practically used in the semiconductor industry. This review begins with a brief summary of previous efforts to model and construct diamond-based high-voltage switching diodes, high-power/high-frequency field-effect transistors, MEMS/NEMS, and devices operating at high temperatures. Following that, we will discuss recent developments to address scalable diamond device applications, emphasizing the synthesis of large-area, high-quality CVD diamond films and difficulties in diamond doping. Lastly, we show potential solutions to modulate diamond’s electronic properties by the “elastic strain engineering” strategy, which sheds light on the future development of diamond-based electronics, photonics and quantum systems.
An equiatomic CoCrFeMnNi high-entropy alloy (HEA) thin film coating has been successfully developed by high-vacuum Radio Frequency (RF) magnetron sputtering. The deposition of a smooth and homogenous ...thin film with uniformly distributed equiaxed nanograins (grain size ~ 10 nm) was achieved through this technique. The thin film coating exhibits a high hardness of 6.8 ± 0.6 GPa, which is superior compared to its bulk counterpart owing to its nanocrystalline structure. Furthermore, it also shows good ductility through nanoindentation, which demonstrates its potential to serve as an alternative to traditional transition metal nitride or carbide coatings for applications in micro-fabrication and advanced coating technologies.
The exchange of heat and momentum between the ocean and the atmosphere greatly affects the growth of typhoons. Utilizing the meteorological and oceanic variables observed by a Drifting Air-sea ...Interface Buoy (DrIB) during Typhoon Molave, a new air-sea turbulent fluxes product (referred to as DrIB product) is developed with the consideration of the thermal and dynamic effects of sea spray in the Coupled Ocean Atmosphere Response Experiment algorithm. The performances of two reanalysis products, ERA5 and MERRA2, under typhoon conditions are evaluated by comparing them to the DrIB observations. In particular, the air-sea turbulent fluxes during Typhoon Molave are systematically studied. The averaged heat (momentum) flux of the DrIB product is ~200% (~30%) higher than the reanalysis. However, the reanalysis products have higher latent heat than the DrIB product, because the reanalysis products have lower wind speed, smaller air-sea temperature difference, and drier atmosphere. The sea spray-induced mean heat (momentum) flux increase is ~1% (8%) in normal weather and is ~5% (17%) at the during-typhoon stage. Sea spray amplifies the dominance of wind speed on heat fluxes and weakens the contribution of air-sea temperature and humidity differences to heat fluxes. Sea spray starts to obviously contribute to the heat fluxes at a 10-m wind speed of ~10 m/s, and it non-linearly accelerates the air-sea heat exchange at a 10-m wind speed of ~20 m/s. When the 10-m wind speed is less than 20 m/s, the basic momentum flux (without sea spray effects) at the air-sea interface is roughly one or two orders of magnitude higher than the sea spray-induced momentum flux. Including the sea spray effects, the maximum momentum flux can even double at the 10-m wind speed of ~30 m/s.
In recent years, the GPS wave buoy has been developed for in situ wave monitoring based on satellite GPS signals. Many research works have been completed on the GPS-based wave measurement technology ...and great progress has been achieved. The basic principle of the GPS wave buoy is to calculate the movement velocity of the buoy using the Doppler frequency shift of satellite GPS signals, and then to calculate the wave parameters from the movement velocity according to ocean wave theory. The shortage of the GPS wave buoy is the occasional occurrence of some unusual values in the movement velocity. This is mainly due to the fact that the GPS antenna is occasionally covered by sea water and cannot normally receive high-quality satellite GPS signals. The traditional solution is to remove these unusual movement velocity values from the records, which requires furthering extend the acquisition time of satellite GPS signals to ensure there is a large enough quantity of effective movement velocity values. Based on the traditional GPS wave measurement technology, this paper presents the algorithmic flow and proposes two improvement measures. On the one hand, the neural network algorithm is used to correct the unusual movement velocity data so that extending the acquisition time of satellite GPS signals is not necessary and battery power is saved. On the other hand, the Gaussian low-pass filter is used to correct the raw directional wave spectrum, which can further eliminate the influence of noise spectrum energy and improve the measurement accuracy. The on-site sea test of the SBF7-1A GPS wave buoy, developed by the National Ocean Technology Center in China, and the gravity-acceleration-type DWR-MKIII Waverider buoy are highlighted in this article. The wave data acquired by the two buoys are analyzed and processed. It can be seen from the processed results that the ocean wave parameters from the two kinds of wave buoys, such as wave height, wave period, wave direction, wave frequency spectrum, and directional wave spectrum, are in good consistency, indicating that the SBF7-1A GPS wave buoy is comparable to the traditional gravity-acceleration-type wave buoy in terms of its accuracy. Therefore, the feasibility and validity of the two improvement measures proposed in this paper are confirmed.
Because of its ultrahigh hardness, synthetic diamond has been widely used in advanced manufacturing and mechanical engineering. As an ultra-wide bandgap semiconductor, on the other hand, diamond ...recently shows a great potential in electronics industry due to its outstanding physical properties. However, like silicon-based electronics, the electrical properties of diamond should be well modulated before it can be practically used in electronic devices. In this work, we briefly review the recent progresses in producing high-quality, electronic grade synthetic diamonds, as well as several typical strategies, from the conventional element doping to the emerging "elastic strain engineering," (ESE) for tuning the electrical and functional properties of microfabricated diamonds. We also briefly show some device application demonstrations of diamond and outline some remaining challenges that are impeding diamond's further practical applications as functional devices and offer some perspective for future functional diamond development.
The TiSiCN coatings were fabricated on Ti6Al4V. The effect of carbon contents on the structure and tribocorrosion properties were studied. The coatings consist of TiN, TiC and Ti(C,N) ...nanocrystallites, amorphous Si3N4, SiC and little amorphous carbon. The coating (11.9at% C) exhibits maximum hardness of 39.8GPa and the best tribocorrosion resistance, which is attributed to the special nanocomposite structure, and the lower friction coefficient of the TiSiCN coating associated with the graphitization effect during sliding in atmosphere. Moreover, the results of tribocorrosion indicate that the volume loss of TiSiCN coatings ascribed to main wear loss and a little corrosion loss, and the synergy between wear and corrosion is a key factor in degenerating the TiSiCN coating.
•Nanocystallites/amorphous structures are observed in TiSiCN coatings.•The TiSiCN coating with 22.22at% C has an excellent self-lubricating.•The TiSiCN coating with 11.93at% C has the best tribocorrosion resistance.•Synergistic action of wear and corrosion accelerates the failure of the coating.
A composite TiSiN/Ag/TiSiN multilayer coating was deposited on a Ti6Al4V substrate by multi-arc ion plating system. The coating had a special structure with a TiN buffer layer, TiSiN/Ag multilayers ...that possess alternating TiSiN (45 nm) and Ag (12 nm) layers, and TiSiN coating interlayers of 120 nm thickness for a total thickness of 1.7 μm. The TiSiN layers had a nanocrystalline/amorphous microstructure of nc-TiN, nc-Ag and amorphous Si3N4, with amorphous Si3N4 present around nanocrystal TiN and Ag boundaries, and Ag layers consisting of ductile nanocrystal silver. We have shown that this design of the composite TiSiN/Ag/TiSiN multilayer coating can effectively hinder crack propagation and increase fracture resistance of the coating.
•The coating is composed of TiSiN coating interlayer and TiSiN/Ag multilayer.•Indentation and scratch tests were used to evaluate the fracture resistance.•The coating showed a significant improved fracture resistance.•The multilayer effectively hinders the crack propagation.
Hardness and elastic modulus of TiSiN coating (C1) and TiSiN/Ag multilayer coatings with different thickness of individual Ag layers of 33.87nm (C2), 30.01nm (C3), 26.67nm (C4), 22.22nm (C5) and ...10.67nm (C6), together with SEM micrographs of indention morphologies after Vickers indentation tests.
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•TiSiN/Ag multilayer coatings design for microstructure was shown by cross-sectional SEM micrographs.•The TiSiN/Ag multilayer coatings showed a significantly improved toughness compared with the TiSiN coating.•The individual Ag layers as a self-lubricating.•TiSiN/Ag multilayer coating (individual Ag layers of 22.22nm) exhibits high hardness, H/E and H3/E*2 values and excellent wear resistance.
The TiSiN/Ag multilayer coatings deposited on Ti6Al4V alloy substrate using the multi-arc ion plating system. All multilayer coatings had a same total thickness of about 2.5μm, and the TiSiN layer had a fixed thickness and the Ag layer had different thicknesses. Evidence concluded from X-ray diffraction, scanning electron microcopies, X-ray photoelectron spectroscopy revealed that nanocrystallites and amorphous microstructure of nc-TiN and amorphous Si3N4 for individual TiSiN layers, where amorphous Si3N4 around nanocrystallites TiN boundaries, and ductile nanocrystallites silver clusters and metallic silver for individual Ag layers which can limit continuous growth of single (200) preferential orientation coarse columnar TiN crystal. In addition, the TiN grain size presented a decreasing trend with the decrease of the thickness of Ag layers. The TiSiN/Ag multilayer coatings showed a significantly improved toughness compared with the TiSiN coating. The individual Ag layers of nano-multilayer coatings, not only as a self-lubricating but also as a barrier which inhibited micro cracks propagation, the formation of threading defects throughout all coatings, cause energy dissipation by passing through the interface zones without making the coating fail and at the same time prevented the aggressive seawater through the micro-pores. Moreover, improved toughness, excellent wear resistance together with high hardness, H/E and H3/E*2 values were found for the TiSiN/Ag multilayer coating with the individual Ag layers of 22.22nm.
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