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Controlling the shape and internal strain of nanowires (NWs) is critical for their safe and reliable use and for the exploration of novel functionalities of nanodevices. In this work, transmission electron microscopy was employed to examine bent Si NWs prepared by asymmetric electron-beam evaporation. The asymmetric deposition of Cr caused the formation of nanosized amorphous-Si domains; the non-crystallinity of the Si NWs was controlled by the bending radius. No other intermediate crystalline phase was present during the crystalline-to-amorphous transition, indicating a direct phase transition from the original crystalline phase to the amorphous phase. Moreover, amorphous microstructures caused by compressive stress, such as amorphous Cr domains and boxes, were also observed in the asymmetric Cr layer used to induce bending, and the local non-crystallinity of Cr was lower than that of Si under the same bending radius.

The applications of two-dimensional (2D) materials in electronics, optoelectronics, and spintronics are limited by the high contact resistance at the metal/semiconductor interface owing to the strong Fermi-level pinning. In this study, an interlayer insertion strategy is proposed to solve this problem, and first principles calculations are done to study the influences of inserting a SiC layer on the Schottky barrier and electronic properties of MoS2/metals (Mg, Al, In, Cu, Ag, Au, Pd, Ti, and Sc). The average charge value substantially increased (≥0.060 e) at the interface between SiC and MoS2 layers, and then no tunneling barrier appeared except for the MoS2/Au contact by inserting the SiC layer. Moreover, ΦSB,N almost decreases for the MoS2/metal contacts by inserting the SiC layer. When Ti, Cu, Au, and Pd are used as electrodes, the n-type Schottky barrier is formed with the ΦSB,N values of 0.479 eV, −0.073 eV, 0.498 eV, and 0.225 eV, respectively. However, if Al, In, Mg, and Ag are used as electrodes, the systems are transformed into Ohmic contact. These findings provide a practical guideline for depinning the Fermi level at contact interfaces and designing the high performance TMD-based nanoelectronic devices.

An aquaponic system in urban area was designed and combined fish culture with sprouts production in a closed-loop system that mimics the ecology of the nature. In order to quantify the nutrients content of sprouts grown under different conditions, we conducted a factorial experiment with 3 types of growth conditions, routine cultivation (RC), circulating water supplement cultivation (CWSC) and aquaponic system cultivation (ASC), then produce sprouts (soybean sprouts, mung bean sprouts, pea sprouts and radish sprouts) under these conditions. The results showed that each sprout under ASC condition, height, weight (10 sprouts), vitamin C content, protein content and soluble sugar content were significantly higher than those under RC condition and CWSC condition. Each sprout showed significant difference in height, weight (10 sprouts), vitamin C content and soluble sugar content. The presence of Carassius auratus auratus can significantly promote the growth of sprouts in aquaponic system, and increase nutrients content. Therefore, aquaponic system can be promoted vigorously in urban areas

The flat-plate blackbody (FPB) is the core device in infrared remote sensing radiometric calibration for providing accurate infrared radiation energy. The emissivity of an FPB is an important parameter that directly affects calibration accuracy. This paper uses a pyramid array structure based on the regulated optical reflection characteristics to analyze the FPB’s emissivity quantitatively. The analysis is accomplished by performing emissivity simulations based on the Monte Carlo method. The effects of specular reflection (SR), near-specular reflection (NSR), and diffuse reflection (DR) on the emissivity of an FPB with pyramid arrays are analyzed. In addition, various patterns of normal emissivity, small-angle directional emissivity, and emissivity uniformity are examined under different reflection characteristics. Further, the blackbodies with the NSR and DR are fabricated and tested experimentally. The experimental results show a good agreement with the corresponding simulation results. The emissivity of the FPB with the NSR can reach 0.996 in the 8–14 µm waveband. Finally, the emissivity uniformity of FPB samples at all tested positions and angles is better than 0.005 and 0.002, respectively. The standard uncertainty of experimental measurement of waveband emissivity and spectral emissivity are 0.47% and 0.38% respectively, and the simulation uncertainty is 0.10%.

Excitonic energy transfer among the zinc chlorin molecules is significant for the photovoltaic process because of their high sensitivities to harvesting sunlight. Zinc chlorin monomers and dimers can be synthesized experimentally, and they can form various self-assembled structures. Using the realistic parameters of zinc chlorin molecules, we assume that 20 molecules with J-, H- or J–H aggregation are arranged in a line and we investigate their dipole configuration effect on exciton dynamics. The expectation value approximation of operators is applied to derive the equations of motion of multi-exciton states. The temporal evolution of multi-exciton states is analyzed in the scheme of density matrix theory. Our simulations show that the inter-molecular coupling results in an exciton band and the wave-packet progressing excited by the resonant laser pulse exhibits attractive or repulsive behavior at the exciton level due to the dipole configuration effect. In the defined J–H coupling, the coherent wave-packet cannot overcome the configuration barrier to the no-excited part. The exciton dynamics revealed here might be helpful to better understand the energy transfer process in organic photovoltaic devices.

The applications of two-dimensional (2D) materials in electronics, optoelectronics, and spintronics are limited by the high contact resistance at the metal/semiconductor interface owing to the strong Fermi-level pinning. In this study, an interlayer insertion strategy is proposed to solve this problem, and first principles calculations are done to study the influences of inserting a SiC layer on the Schottky barrier and electronic properties of MoS2/metals (Mg, Al, In, Cu, Ag, Au, Pd, Ti, and Sc). The average charge value substantially increased (≥0.060 e) at the interface between SiC and MoS2 layers, and then no tunneling barrier appeared except for the MoS2/Au contact by inserting the SiC layer. Moreover, ΦSB,N almost decreases for the MoS2/metal contacts by inserting the SiC layer. When Ti, Cu, Au, and Pd are used as electrodes, the n-type Schottky barrier is formed with the ΦSB,N values of 0.479 eV, -0.073 eV, 0.498 eV, and 0.225 eV, respectively. However, if Al, In, Mg, and Ag are used as electrodes, the systems are transformed into Ohmic contact. These findings provide a practical guideline for depinning the Fermi level at contact interfaces and designing the high performance TMD-based nanoelectronic devices.

The quantum interference effect offers a unique route to control the charge transport through nanoscale constrictions. The carbon atomic chain, which is an sp-hybridized carbon allotrope, has recently stimulated interest to construct ultimate nano-devices. Instead of using the carbon atomic chain as an electron transmitting channel interconnecting nano-components, we explore the possibility of using side carbon chains to change the phase of the transmitting electrons and influence the interference pattern of the nano-device. Interference pattern modulation is a general phenomenon which is demonstrated in a benzene molecular device, a zigzag graphene nanoribbon device and a SiC nanoribbon device. Odd-even oscillation dependence of the conductance on the length of the side carbon chain is found. Two criteria, i.e. large magnitude of the local state in the side carbon chain and proper length of the side carbon chain, must be satisfied simultaneously to achieve effective interference modulation. By carefully choosing the position and length of the side carbon chains, the transmission zero can be moved to the Fermi energy. Moreover, the transmission zero induced by destructive interference at the Fermi energy can be very robust against strain. This work provides a new possibility to construct nano-devices with carbon atomic chains.

Within the framework of two-component pseudo-potentials, the coupled-cluster theory with spin-orbit interaction and the equation-of-motion coupled-cluster theory with spin-orbit interaction for ionized states are employed to obtain the spectroscopic constants of the ground-state Cu2, Ag2, and Au2 in this work. The spin-orbit interaction is only calculated iteratively in the post-Hartree-Fock, i.e. the coupled-cluster procedure. It is shown that the CCSD(T) approach with spin-orbit interaction is capable of providing the rather accurate equilibrium distances and harmonic frequencies. Furthermore, the equation-of-motion coupled-cluster approach with spin-orbit interaction for ionized states is able to reasonably estimate the spin-orbit contribution to the binding energy. Hence, the accurate binding energies are obtained by the scalar-relativistic CCSD(T) calculations with the correction of spin-orbit contribution. In addition, the spectroscopic constants have a weak basis set dependence for all the title species.

The flexibility and quasi-one-dimensional nature of nanowires offer wide-ranging possibilities for novel heterostructure design and strain engineering. In this work, we realized controllably bent Si nanowires by using asymmetric growth with electron beam evaporation system. It is demonstrated that the degree of arc-bending depends on the deposition angle and deposition thickness. The forward bending of the Si nanowires is due to the lattice mismatch and thermal mismatch between Si and the metallic materials such as Cr and Ti, which can be generally utilized to control the shape and internal strain of Si nanowires, with potential applications for fabricating desired nano-devices.

Understanding the interfacial properties between two-dimensional (2D) semiconductors and metal electrodes is vital for designing and realization of electronic devices. In this paper, first-principle calculations are done to study the influences of the defects on the interfacial electronic states of mMoS2/metal (metal= Mg, Al, In, Cu, Ag, Au, and Pd). It is found that the electron states at the interface are substantially increased if defects are induced in mMoS2 contacted with metals. As a result, the tunneling barrier is reduced. The Schottky barrier height (SBH) is increased in mMoS2 contacted with Mg, Al, In, and Au, but is reduced in defective mMoS2 contacted with Cu, Ag, and Pd. Furthermore, the pinning factor S are 0.227, 0.238, and 0.238 for the VS, VMo, and SMo in mMoS2, but the S value is only 0.030 for substitution of S by Mo (MoS) in mMoS2. Our findings are in good agreement with the experimental results. The results give insight into the contact physics of 2D semiconductors with metals and it is suggested that defects play a key role on the future generation electronic applications.

The CCSD(T) approach based on two-component relativistic effective core potential with spin–orbit interaction just included in coupled cluster iteration is adopted to study the spectroscopic constants of ground states of Kr 2 , Xe 2 and Rn 2 dimers. The spectroscopic constants have significant basis set dependence. Extrapolation to the complete basis set limit provides the most accurate values. The spin–orbit interaction hardly affects the spectroscopic constants of Kr 2 and Xe 2 . However, the equilibrium bond length is shortened about 0.013 A and the dissociation energy is augmented about 18 cm −1 by the spin–orbit interaction for Rn 2 in the complete basis set limit.

In order to realize a flexible visible-near-infrared (VIS-NIR) photodetector, Si nanowires (SiNWs) were prepared on graphene (Gr) by using metal-catalyzed chemical vapor deposition, and then the Gr/SiNWs heterojunction was transferred onto a flexible polytetrafluoroethylene (PTFE) substrate by using a polymethylmethacrylate (PMMA)/polydimethylsiloxane (PDMS) as a double-layer support film. The transfer process of the flexible Gr/SiNWs heterojunction was successful. However, the mechanical stress induced by the spin coating process and volume shrinkage of the PMMA/PDMS layers had an impact on the crystalline structure of the SiNWs. The as-fabricated Gr/SiNWs heterojunction photodiode indicated rectifying behavior. Under VIS-NIR illumination of 0.1 W/cm2, an apparent operation of the photodiode with a photoelectric effect was observed.

By applying a single or double stimulating pulse to a conjugated polymer, we theoretically realize the population inversion between the generated intragap states. The simulations are performed within the framework of an extended version of the one-dimensional Su–Schrieffer–Heeger tight-binding model combined with a nonadiabatic evolution method. In discussions, we mainly compare the stimulating intensity thresholds between the two different pumped modes, at which the population inversion in polymer is reached. It is found that, the stimulating intensity threshold can be remarkably reduced by employing a double pulse rather than a single one. Effect of the lasting time for each pulse on the threshold is also discussed. We then propose a new optical-pumped mode to realize the population inversion in polymers, which is potentially of great importance for polymer lasers.