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The novel broadband avalanche photodetectors based on 2-D/3-D van der Waals (vdWs) heterostructures provide a new approach for next-generation photoelectric devices. Herein, an avalanche photodetector based on WS2/Ge heterojunction with a top gate is readily realized. The ultralow dark current ( $1 \times 10^{-{10}}$ A) is obtained in the device under a gate voltage of -1 V. The photovoltaic effect allows the device to operate under zero bias with considerable responsivity (0.36/0.009 A/W) and detectivity ( $8.2 \times 10^{{11}}$ / $2.06 \times 10^{{10}}$ jones) at 532/1550 nm. The carrier multiplication caused by avalanche breakdown in the device is also observed, resulting in the high responsivity of 92 and 3.4 A/W and the maximum gain of 6 and 175 under 532 and 1550 nm illumination, respectively. Based on the ultralow dark current and the breakdown voltage (5.0 V), as well as the broad detection region covering the visible and near-infrared range, the WS2/Ge broadband avalanche photodetector is promising for the broadband and low-energy-consumption detector applied in optical communication and laser radar imaging.

The photodetector in the near-infrared band is playing an increasingly important role in various industries such as optical communication, environmental detection, and biomedical imaging. In this article, we report on an $8\times 8$ array of all germanium (Ge)-based vertical p-n photodetectors enhanced by Ge nanopillars. These nanopillars can significantly improve the light absorption efficiency in a broad spectral range and suppress the dark current; therefore, the broadband enhancement of responsivity and specific detectivity from 550 to 1800 nm is observed in the device. In particular, the maximum enhancement factor of responsivity and specific detectivity at 1550 nm is over 112.59% and 279.9%, respectively, under the −1-V bias voltage. When avalanche breakdown is reached under a bias over −9 V, the ultraresponsivity (161.67 A/W) and gain (53.83) are also obtained in the device with nanopillars. These results indicate that the detection ability of Ge avalanche detectors can be efficiently improved by photon-trapping nanostructures, which helps for the rapid development of group IV photodetectors.

Si-based emitters have been of great interest as an ideal light source for monolithic optical-electronic integrated circuits (MOEICs) on Si substrates. However, the general Si-based material is a diamond structure of cubic lattice with an indirect band gap, which cannot emit light efficiently. Here, hexagonal-Ge (H–Ge) nanostructures within a light-emitting metasurface consisting of a cubic-SiGe nanodisk array are reported. The H–Ge nanostructure is naturally formed within the cubic-Ge epitaxially grown on Si (001) substrates due to the strain-induced nanoscale crystal structure transformation assisted by far-from-equilibrium growth conditions. The direct-bandgap features of H–Ge nanostructures are observed and discussed, including a rather strong and linearly power-dependent photoluminescence (PL) peak around 1562 nm at room temperature and temperature-insensitive PL spectrum near room temperature. Given the direct-bandgap nature, the heterostructure of H–Ge/C-Ge, and the compatibility with the sophisticated Si technology, the H–Ge nanostructure has great potential for innovative light sources and other functional devices, particularly in Si-based MOEICs.

AbstractHaixin Bridge in Guangzhou is a half-through inclined arch bridge with a main span of 198 m. A curved girder with a standard deck width of 15 m is used, making this bridge the largest and most complex of its kind in the world. Since its opening on 25 June 2021, Haixin Bridge, with minimalistic geometric curves, has created a multi-purpose urban public space with distinctive features of regional traditional culture amidst the mushrooming modern buildings in the central business district (CBD) of Guangzhou. Now it is a popular place much favored and recognized by local citizens, primarily attributable to the structural design of the bridge, which aims not merely at optimal structure and minimal cost, but more importantly at the unity of function, aesthetics and technology.

A high-performance near-infrared (NIR) hybrid MSM Ge photodetector is proposed in this work, and the properties of this device can be significantly enhanced by the hybrid structure consisting of Ge nanopillar arrays and Au nanoparticles (Au NPs). The responsivity of this hybrid device at 1550 nm could reach 0.572 A/W, which is 4.17 times larger than that of the planar Ge photodetector. The responsivity enhancement is related to the light trapping effect of nanopillar arrays, the electrostatic effect, and the Fermi pinning effect. The light trapping effect of nanopillar arrays can effectively improve the absorption of the Ge photodetector, while the electrostatic effect enhances the spatial electron–hole separation and suppresses the recombination rate. Moreover, the Fermi pinning effect can lower the Schottky barrier of Au/Ge interface. Our results showed a new light on the high-performance Ge photodetector by hybridization of nanopillar arrays and Au NPs. The presented hybrid Ge photodetector will have great potential for application in innovative optoelectronic devices, particularly as a high-performance NIR photodetector for optical communication.

Predicting solubility of small molecules is a very difficult undertaking due to the lack of reliable and consistent experimental solubility data. It is well known that for a molecule in a crystal lattice to be dissolved, it must, first, dissociate from the lattice and then, second, be solvated. The melting point of a compound is proportional to the lattice energy, and the octanol–water partition coefficient (log P) is a measure of the compound’s solvation efficiency. The CCDC’s melting point dataset of almost one hundred thousand compounds was utilized to create widely applicable machine learning models of small molecule melting points. Using the general solubility equation, the aqueous thermodynamic solubilities of the same compounds can be predicted. The global model could be easily localized by adding additional melting point measurements for a chemical series of interest.

Improving detection efficiency of Ge photodetector near the absorptance edge is crucial for fiber-optic telecommunication. Here, we report the unique photodetection properties of germanium (Ge) metal–semiconductor–metal (MSM) photodetector with Ge micropillar array. The responsivity and detectivity of the device at 1550 and 1990 nm are studied. When compared with the Ge photodetector without micropillar, the responsivity and detectivity of micropillar Ge device are improved by 2.76 and 4.21 times at 1550 nm, respectively. This phenomenon is mainly associated with the enhanced absorption efficiency by geometrical light trapping effect and guided modes supported in the micropillar array. Particularly, the values of responsivity and detectivity in the device with Ge micropillar array are enhanced over 29.9 and 37.1 times at 1990 nm than the results in the device without micropillar, which are quite larger than the values at 1550 nm. This feature is related to that the suitable position of absorption enhancement caused by the micropillar array, which can result in the efficiently separation and suppressed recombination of photogenerated carriers under bias voltage. This work provides a feasible approach to broaden the detection wavelength of Ge-based photodetectors, enhance the absorption near the absorption edge, and improve the detection performance.

AbstractMingzhuwan Bridge is currently the largest span three-main-truss steel arch bridge, with a main span of 436 m. It was opened to traffic on 28 June 2021. The upper structure adopts a three-main-truss arch-beam combination system, the main arch is an N-type truss of variable height and the main girder is an N-type truss of constant height. The main girder truss is arranged with double decks, and the suspenders are made of high-strength parallel wire cables. The deck system adopts an orthotropic steel deck. This technical report mainly introduces the technical characteristics of the three-main-truss space truss structure, rigid arch and rigid beam structure, and synchronous construction of arch and beam.

This article presents an evaluation of the CMOS logic performance of a junctionless (JL) forksheet based on 3-D numerical simulation. The study investigates the transfer characteristics and gate capacitance of the JL-forksheet with channel doping ranging from ${1} \times {10}^{{19}}$ to ${6} \times {10}^{{19}}/\text {cm}^{{3}}$ , to determine the optimal performance of the device. Results show that due to its lower gate capacitance, the JL-forksheet has a lower intrinsic delay than the IM-forksheet. Moreover, the JL-forksheet demonstrates improved logic performance in terms of rise time, fall time, propagation delay, and maximum oscillation frequency, with improvements of at least 25%, 35%, 17%, and 21%, respectively, as compared to the IM-forksheet. Based on its simple fabrication process, better power efficiency, and improved digital logic performance at the sub-2 nm technology node (N2), the JL-forksheet exhibits strong potential as a high-performance CMOS logic solution in the post-Moore era.

The heterostructures between atomically thin 2-D and 3-D semiconductors show great potential for high-performance photodetector. In this work, the efficient light detection of the p-n and p-p+ black phosphorus (bP)/germanium (Ge) heterojunction photodiode has been demonstrated. With the change of Ge doping type, the rectification direction of the heterojunction diode formed by bP and Ge could be reversed. Due to the enhanced photocarrier separation at the reverse bias, the bP/n-Ge (bP/p-Ge) device has a responsivity of 6.08 (3.43) A/W under 1550-nm illumination, with fast response speed in the 10- $\mu \text{s}$ level. The bP/n-Ge device has a significant photovoltaic effect due to the small conduction band energy offset, with a large open-circuit voltage of 0.34 V. Under the illumination of light with different polarization directions, the device exhibits apparent polarization-sensitive detection, and the dichroic ratio of bP/n-Ge and bP/p-Ge devices is 4.25 and 3.85, respectively. These results suggest that the bP/Ge heterojunction photodetector would have great potential in high-performance, self-powered, and polarization-sensitive photodetection.

In this article, a SiGe shell complementary FET (CFET) composed of an inversion mode (IM) nFET and a junctionless accumulation mode pFET under 2-nm (N2) and 1.5-nm (N1.5) technology nodes was studied for the characteristics of a single device and the CMOS logic circuit using 3-D numerical simulation. A comparison study between Si shell nanosheet and SiGe shell CFET with a Ge mole fraction in the range of 0.5–0.9. Compared with the Si shell nanosheet (NS), the SiGe shell CFET improves the ON-state current, transconductance, transition frequency, and intrinsic delay up to 29%, 32%, 31%, and 21%, respectively. Due to the mobility improvement in SiGe shell CFET, the fall time, rise time, propagation delay, and maximum operating frequency of the $\text {Si}_{{0.5}}\text {Ge}_{{0.5}}$ shell CFET are also improved up to 2%, 43%, 3%, and 3%, respectively, compared with their Si shell counterparts. This SiGe shell CFET has a lower parasitic RC, a smaller layout area, and better analog and digital performance at the sub-2-nm technology node. This makes it a promising architecture for future high-performance CMOS logic applications.

An artificial retina system shows a promising potential to achieve fast response, low power consumption, and high integration density for vision sensing systems. Optoelectronic sensors, which can emulate the neurobiological functionalities of retinal neurons, are crucial in the artificial retina systems. Here, we propose a WSe2phototransistor with asymmetrical van der Waals (vdWs) stacking that can be used as an optoelectronic sensor in artificial retina systems. Through the utilization of the gate-tunable self-powered bidirectional photoresponse of this phototransistor, the neurobiological functionalities of both bipolar cells and cone cells, as well as the hierarchical connectivity between these two types of retinal neurons, are successfully mimicked by a single device. This self-powered bidirectional photoresponse is attributed to the asymmetrical vdWs stacking structure, which enables the transition from an n–p to p+–p homojunction in the WSe2channel under different polarities of gate bias. Moreover, the detectivity and ON/OFF ratio of this phototransistor reach as high as 1.8 × 1013Jones and 5.3 × 104, respectively, and a rise/fall time <80 μs is achieved, as well, which reveals good photodetection performance. The proof of this device provides a pathway for the future development of neuromorphic vision devices and systems.

The dramatic increase in the prevalence of multi-drug resistant Gram-negative bacterial infections and the simultaneous lack of new classes of antibiotics is projected to result in approximately 10 million deaths per year by 2050. We report on efforts to target the Gram-negative ATP-binding cassette (ABC) transporter MsbA, an essential inner membrane protein that transports lipopolysaccharide from the inner leaflet to the periplasmic face of the inner membrane. We demonstrate the improvement of a high throughput screening hit into compounds with on-target single digit micromolar (μM) minimum inhibitory concentrations against wild-type uropathogenic Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae. A 2.98 Å resolution X-ray crystal structure of MsbA complexed with an inhibitor revealed a novel mechanism for inhibition of an ABC transporter. The identification of a fully encapsulated membrane binding site in Gram-negative bacteria led to unique physicochemical property requirements for wild-type activity.

A Ge metal–semiconductor–metal photodetector covered with asymmetric HfSe_2 contact geometries has been proposed to realize high-performance unbiased photodetection at 1550 nm. At -1 V bias, the responsivity of this device shows a 71% improvement compared to the device without HfSe_2. Moreover, the responsivity and detectivity of this device at zero bias can reach to 71.2 mA/W and 3.27×10^10 Jones, respectively. Furthermore, the fall time of this device is 2.2 µs and 53% shorter than the device without HfSe_2. This work provides a feasible way to develop unbiased Ge-based photodetectors in the near-IR communications band.

Pim kinases have been targets of interest for a number of therapeutic areas. Evidence of durable single-agent efficacy in human clinical trials validated Pim kinase inhibition as a promising therapeutic approach for multiple myeloma patients. Here, we report the compound optimization leading to GDC-0339 (16), a potent, orally bioavailable, and well tolerated pan-Pim kinase inhibitor that proved efficacious in RPMI8226 and MM.1S human multiple myeloma xenograft mouse models and has been evaluated as an early development candidate.

The movement of core-lipopolysaccharide across the inner membrane of Gram-negative bacteria is catalysed by an essential ATP-binding cassette transporter, MsbA. Recent structures of MsbA and related transporters have provided insights into the molecular basis of active lipid transport; however, structural information about their pharmacological modulation remains limited. Here we report the 2.9 Å resolution structure of MsbA in complex with G907, a selective small-molecule antagonist with bactericidal activity, revealing an unprecedented mechanism of ABC transporter inhibition. G907 traps MsbA in an inward-facing, lipopolysaccharide-bound conformation by wedging into an architecturally conserved transmembrane pocket. A second allosteric mechanism of antagonism occurs through structural and functional uncoupling of the nucleotide-binding domains. This study establishes a framework for the selective modulation of ABC transporters and provides rational avenues for the design of new antibiotics and other therapeutics targeting this protein family. Crystal structures of the ABC transporter MsbA in complex with two selective small-molecule antagonists reveal an unprecedented allosteric mechanism of inhibition.

Currently, the scale of dc distributed power systems (DPSs) is experiencing a sustained high-speed growth, which makes stability analysis become a complicated but essential problem. This paper has proposed decentralized impedance specifications for small-signal stability of a dc DPS which contains one voltage source subsystem, multiple power controlled source subsystems and multiple load subsystems. The proposed method defines invariant impedance specifications for each subsystem of the DPS, which only depend on the rated dc bus voltage and the rated capacity of each subsystem. The decentralized invariant impedance specifications make it possible that each subsystem is designed individually and the small-signal stability of the DPS is guaranteed at the same time. The proposed method can be applied to both large-scale and plug-and-play dc DPSs, whose stability analyses with conventional approaches would suffer from the curse of dimensionality and changing parameters. The proposed method is verified by hardware-in-loop tests.

The carrier mobility of Si material can be enhanced under strain, and the stress magnitude can be measured by the Raman spectrum. In this paper, we aim to study the penetration depths into biaxially-strained Si materials at various Raman excitation wavelengths and the stress model corresponding to Raman spectrum in biaxially-strained Si. The experimental results show that it is best to use 325 nm excitation to measure the material stress in the top strained Si layer, and that one must pay attention to the distortion of the buffer layers on measuring results while 514 nm excitation is also measurable. Moreover, we established the stress model for Raman spectrum of biaxially-strained Si based on the Secular equation. One can obtain the stress magnitude in biaxially-strained Si by the model, as long as the results of the Raman spectrum are given. Our quantitative results can provide valuable references for stress analysis on strained materials.

Previous studies have reported that vitexins induce cytotoxic effects. In the present study, we investigate a new native lignan vitexin 6 (VB6) in vitroto determine the molecular mechanism underlying its cytotoxicity. We screened and cultured several tumor cell lines and subsequently analyzed VB6 cytotoxicity against 14 different tumor cell lines using a 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The expression of proteins that regulate apoptosis and autophagy was determined using western blot analysis. VB6 showed an excellent cytotoxic effect against various cancer cell lines in vitro. It induced apoptosis and autophagy of cancer cells. VB6-induced apoptosis showed a time-dependent and concentration-dependent relationship with cleaved poly (ADP-ribose) polymerase, cleaved caspase-3, Bax upregulation, and Bcl-2 downregulation. The levels of Beclin-1 and LC3-II, which are markers for cell autophagy, gradually increased after VB6 treatment. Jun N-terminal kinase (JNK) phosphorylation was increased after VB6 treatment, accompanied by upregulation of P-Bcl-2 and P-C-Jun expression. Cotreatment with a JNK inhibitor significantly decreased VB6-induced cell death and downregulated P-Bcl-2, and cleaved PARP and Beclin-1 expression. The new native lignan VB6 inhibits cancer cell proliferation by activating the JNK pathway. We believe that VB6 could be a valuable chemotherapeutic drug after further evaluation.

Abstract: In this study, the electron effective masses, including longitudinal, transverse, density-of-states and conductivity effective masses, have been systematically investigated in (001), (101) and (111) biaxially strained Si and Si1−x Ge x . It is found that the effect of strain on the longitudinal and transverse masses can be neglected, that the density-of-states masses in (001) and (110) biaxially strained Si and Si1−x Ge x materials decrease significantly with increasing Ge fraction (x), and that the conductivity masses along typical orientations in (001) and (110) strained Si and Si1−x Ge x .are obviously different from those in relaxed Si. The quantitative results obtained from this work may provide valuable theoretical references to understanding strained materials physics and studying conduction channel design related to stress and orientations in the strained devices.

Abstract: The strain technology is an effective way to improve hole mobility and CMOS device performance. Tetragonal strain leading to hole mobility enhancement in strained Si (001) has been verified by two aspects of theories and experiments. In this paper, we aim to study rhombohedral strain effect on the hole mobility of Si, which results from growing on the (111) oriented relaxed Si1−x Ge x substrate. It is found that structure transformation of Si from cubic to trigonal system occurs under the biaxial tensile stress imposed by the (111) substrate and that its corresponding averaged hole mobility increases about one time at most in comparison with one of unstrained Si. The results can provide valuable reference to the understanding of the strained Si material physics and its design.

Abstract: An analytical model for the subthreshold current of a strained-Si metal-oxide-semiconductor field-effect transistor (MOSFET) is developed by solving the two-dimensional (2D) Poisson equation and the conventional drift-diffusion theory. Model verification is carried out using the 2D device simulator ISE. Good agreement is obtained between the model’s calculations and the simulated results. By analyzing the model, the dependence of current on the strained-Si layer strain, doping concentration, source/drain junction depths and substrate voltage is studied. This subthreshold current model provides valuable information for strained-Si MOSFET design.

Abstract: Based on Fermi’s golden rule and the theory of Boltzmann collision term approximation, the hole scattering mechanism of strained Si/(111)Si1−x Ge x was established, including ionized impurity, acoustic phonon, non-polar optical phonon and total scattering rate models. It was found that the total scattering rate of the hole in strained Si/(111)Si1−x Ge x decreased obviously with the increasing stress when energy was 0.04 eV. In comparison with one of the unstrained Si, the total hole scattering rate of strained Si/(111)Si1−x Ge x decreased about 38% at most. The decreasing hole scattering rate enhanced the hole mobility in strained Si materials. The result could provide valuable references to the research on hole mobility of strained Si materials and the design of PMOS devices.

Abstract: The strained Si techique has been widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E-k relations of strained Si/(111)Si1−x Ge x , the valence band and hole effective mass along the [111] and [−110] directions were obtained in this work. In comparison with the relaxed Si, the valence band edge degeneracy was partially lifted, and the significant change was observed band structures along the [111] and [−110] directions, as well as in its corresponding hole effective masses with the increasing Ge fraction. The results obtained can provide valuable references to the investigation concerning the Si-based strained devices enhancement and the conduction channel design related to stress and orientation.

Abstract: The directional, averaged, and density-of-states effective masses of holes have been calculated for strained Si/(111)Si1−x Ge x . The results for the directional effective mass show that the effect of strain makes the constant energy surface of “heavy” holes more obvious warping than that in relaxed Si. The [111] and [110] directional effective masses of “heavy” holes decrease significantly under strain. It is found that the averaged effective mass of “heavy” holes decreases with increasing Ge fraction, while that of “light” holes increases. The traditional concepts of heavy and light holes become insignificant when Ge fraction is close to 0.4. The strain effect monotonically reduces the density-of-states effective mass at 218, 300 and 393 K, respectively.

There is a critical need for new antibacterial strategies to counter the growing problem of antibiotic resistance. In Gram-negative bacteria, the outer membrane (OM) provides a protective barrier against antibiotics and other environmental insults.

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