On December 13, 2022, the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) announced that Lawrence Livermore National Laboratory (LLNL) first achieved the fusion output energy larger than the driving fusion laser energy by its National Ignition Facility (NIF), which was the “ignition” milestone in human history. The most considerable scientific breakthrough in decades provides significant support for national defense security and the development of clean energy. This article reports the interpretation of the difficulties of inertial confinement fusion (ICF) by interviewing professor ZHENG Wanguo, a senior researcher at the Laser Fusion Research Center of the Chinese Academy of Engineering Physics, including the paths to achieve “ignition”, the ignition process of laser fusion, the future development of ICF or inertial fusion energy (IFE), the important role of laser crystals in ICF or IFE and other issues of widespread concern. The professional information may help us to learn more about the development trend of ICF and IFE，and carry out the basic and key technology researches on crystalline materials to support the construction of laser drive devices in the future.

Tb3Ga5O12 crystal is a mainstream commercial material with good magneto-optical performance, but it suffers from serious gallium oxide volatilization during the growth process, which makes it difficult to meet developing requirements in high power applications. Tb3Al5O12 crystal, which shows a large Verdet constant, is difficult to grow due to its incongruent melting nature. Therefore, it is urgent to explore new high-quality magneto-optical crystals to meet the needs in high power applications. In this work, a series of Tb3AlxGa5-xO12 (TAGG) magneto-optical crystals with high aluminum content were grown by the micro-pulling-down method in a mixed atmosphere of high-purity nitrogen and carbon dioxide. The result of the rocking curve shows the as-grown TAGG magneto-optical crystal has high crystal quality. The transmittance spectrum and magneto-optical characteristics test results show that, the TAGG crystal shows a higher transparency and a larger Verdet constant compared with the traditional Tb3Ga5O12 crystal, which is a very promising low-cost magneto-optical material for high power laser systems.

A large NaI(Tl) crystal with a volume of 4 L was grown by Bridgman method. The crystal was tested by X-ray powder diffraction and UV-Visible near-infrared transmission spectroscopy. The results show that the crystal has a single phase and the transmittance is higher than 75% at 600~1 600 nm. The results of inductively coupled plasma emission spectroscopy show that the concentration of Tl ions in the crystal gradually increases from head to tail. After forging, cutting, grinding, polishing and packaging, NaI(Tl) crystal blank was made into square crystal with 100 mm×50 mm×400 mm. The scintillation property measurement shows that the average energy resolution of crystal is 7.9% under the excitation of 137Cs radioactive source, and the relative light output and energy resolution at different locations are different.

Due to the failure of visual inspection to detect the phenomenon of broken edge during the equal-diameter growth process of single crystal silicon, a method based on the ISOMAP-DE-SVM was proposed to give early-warning before the phenomenon of broken edge. Firstly, the parameters with small variance were excluded, redundant parameters were rejected by the spearman correlation coefficient, the nonlinear correlation of remaining parameters was tested by maximal information cofficient. Then, the mean and standard deviation of the key parameters were input into isometric mapping and multiple dimensional scaling, and two samples were obtained. Finally, two samples were input into the support vector machine prediction model optimized by difference algorithm and genetic algorithm respectively, and four results were obtained. The prediction results show that the prediction model based on ISOMAP-DE-SVM can effectively predict the phenomenon of broken edge of single crystal silicon, the prediction model has the characteristics of fast convergence speed and high accuracy, and the average prediction rate can reach 96%. Meanwhile, the method reveals that the data in the equal-diameter growth process of single crystal silicon has nonlinear characteristics. In the practical application verification, it is shown that the model has certain engineering practical value.

In this paper, the effect of introducting different concentration CO2 into reaction gas on the internal stress of single crystal diamond grown by microwave plasma chemical vapor deposition (MPCVD) homogeneous epitaxy was studied, and its mechanism was analyzed. Results show that with the increase of CO2 concentration, the internal stress of single crystal diamond decreases gradually. This is because the added CO2 provides oxygen containing groups, which can effectively etch the non-diamond carbon in the diamond growth process, and reduce the content of impurities in the diamond, so as to avoid lattice distortion and reduce growth defects. This ultimately shows the reduction of the internal stress of single crystal diamond, which is in the form of compressive stress. Besides, the addition of CO2 in reaction gas can reduce the growth rate and deposition temperature of single crystal diamond, and single crystal diamond with less impurities and high crystallinity can be obtained at a suitable carbon hydrogen oxygen atomic ratio (5∶112∶4).

The boron (B)-sulfur (S) co-doped single crystal diamond was prepared by diffusion device using high purity boron powder and sulfur powder at 1 300 ℃ under a high temperature vacuum. In this paper, scanning electron microscopy, X-ray energy spectroscopy, Raman spectroscopy, and other tests show that the morphology and crystal quality of diamond change with doping of the two elements. The co-doping diamond crystal surface morphology is complex, and the internal morphology of etch pits and gully is stepped. With the doping amount increases, the steps appear to fracture, and high content of boron and sulfur atoms is detected at the etch pits. The diamond with B-S mass fraction of 0.5 have the highest content of boron and sulfur atoms at the etch pits. With the impurity atoms infiltration, full width at half maximum of Raman increases, and crystal quality of the diamond decreases. Hall testing at room temperature reveals that the diamond resistivity decreases after doping. The samples with the B-S mass fraction of 1 and 2 exhibit p-type conductivity. While the sample with the B-S mass fraction of 0.5, the Hall coefficient is negative and shows n-type conductivity.

As one of the most important steps in machine processing of 4H-silicon carbide (4H-SiC) wafers, lapping exerts an important impact on the quality of 4H-SiC substrate wafers. In this paper, the effects of diamond abrasive morphology and dispersion medium on the material removal rate and surface parameters of 4H-SiC wafers were investigated. Based on the contact between diamond abrasive and 4H-SiC wafer surface during lapping process, a simple wafer material removal rate model was derived. It is found that the abrasive morphology significantly affects the material removal rate of 4H-SiC substrate wafers, the higher the material removal rate, the smaller the total thickness variation (TTV) is obtained for 4H-SiC substrate wafers. Due to the anisotropy of C-face and Si-face of 4H-SiC, the material removal rate of C-face is higher than that of Si-face. In terms of effect of the dispersion medium, the Zeta potential absolute value of the water-based slurry is high, and the abrasive is evenly dispersed. It is beneficial to control the disc temperature during the lapping process due to the large thermal conductivity of water. The Zeta potential absolute value of the glycol-based slurry is small, and the abrasive is prone to agglomeration. As the abrasive cutting depth deepens in lapping process, the material removal rate of 4H-SiC wafer increases, and the maximum value of scratch depth also aggravates accordingly.

In this paper, the finite element simulation software COMSOL is used to calculate the band-gap of the two-dimensional chiral phononic crystal, and the influence of the scatterer parameters and ligament coating parameters on the band-gap is analyzed. On this basis, the effective parameter design space for the optimal design of the band-gap of chiral phononic crystals is determined; then, based on the ISIGHT optimization design platform, the genetic algorithm is embedded to carry out the optimal design of the band-gap of two-dimensional chiral phononic crystals. In the optimal design process of the band-gap, the effective configuration parameters of the two-dimensional chiral phononic crystal are used as the design variables, and the maximum relative band-gap width is the goal to design the unit cell configuration of the chiral phononic crystal. Then, the optimized unit cell configuration is used as the initial configuration, the effective material parameters of the chiral phononic crystal are used as the design variables, and the maximum relative band-gap width is the goal to further realize the optimal design of the band-gap of the two-dimensional chiral phononic crystal. This work maximizes the potential of optimal design of the band-gap of two-dimensional chiral phononic crystals, and provides a reliable and effective analysis and design method for giving full play to the role of chiral phononic crystals in vibration and noise reduction.

In this paper, a new type of pipeline metastructure is proposed. It’s axial vibration band gaps include both local resonance and Bragg scattering. The structure has two order band gap within 2 500 Hz, and the frequency range of the second order band gap is wide. The energy band structure distribution and finite-period structure transmission characteristics of the structure were calculated by the transfer matrix method and the finite element method respectively. A pipeline metastructure experimental platform with 4 cells was built to test the vibration, and the test data were compared with the calculation results. Finally, the influences of different parameters on the band gap distribution are discussed. The results show that there are two band gaps in the studied pipe metastructure within 2 500 Hz. The first order band gap is mainly local resonant band gap, which is greatly affected by the geometric dimensions of the boss and the vibrator, but less affected by the cell size. The second order band gap is mainly Bragg scattering band gap, and the width of which could reach 923 Hz. The band gap distribution varies with the cell length, boss length and oscillator thickness. The reasonable design of the geometric dimensions of each part of the structure can meet the needs of vibration suppression in specific frequency bands in the project.

A Si doped interlayer was introduced into the GaAs barrier layer to study optical properties of InGaAs/GaAs surface quantum dots (SQDs). Photoluminescence (PL) measurements show that luminescence of InGaAs/GaAs SQDs is strongly dependent on Si doping concentration. With increasing the Si doping concentration, InGaAs/GaAs SQDs show clearly different luminescence characteristics, including: PL peak position of SQDs shifts to red at first and then to blue; the dependence of PL peak energy on the cubic root of excitation intensity changes from linear to nonlinear; configuration interaction method shows reduced blue shift for PL band; time-resolved PL indicates a transition from nonlinear decay of type-II QDs to linear decay of type-I QDs. These experimental results indicate that Si doping fill the surface states and modify the surface Fermi level pinning effect, thus changing the luminescence characteristics of InGaAs/GaAs SQDs. This research provides a support for understanding and tailing the surface-sensitive characteristics of InGaAs SQDs for development of sensors.

In this paper, a double-barrier structure AlGaN-InGaN/GaN MQWs-AlGaN solar cell materials containing high indium components was grown on (001)-oriented patterned sapphire substrate (PSS) by metal organic chemical vapor deposition (MOCVD) technology. Compared with the MQWs solar cell material containing AlGaN electron barrier structure with low indium, it is found that the material of this structure has a smaller full width at half maximum (FWHM) by high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) spectroscopy analysis, and the dislocation density of this structural material is also reduced by an order of magnitude to 107 cm-2 by the dislocation density formula; at the same time, the strain relaxation in the active region decreases by 51%. In addition, luminous intensity of this structural material is enhanced by 35%. The results show that the epitaxial material containing AlGaN double barrier structure can reduce the dislocation density in the active region, decrease the number of non-radiative recombination centers, and increase the number of effective photo-generated carriers in the active region, which provides experimental basis for the preparation of high efficiency solar cells.

The substitution position of indium (In) atoms is significant for developing novel orthorhombic GaN hydrogen storage materials. Currently, research on the influence of In atom substitution position on the orthorhombic GaN is still relatively limited. In this paper, based on the first-principles, formation energy, electronic structure, elastic properties, and mechanical stability of InGaN materials with different In atom substitution positions were studied. The results show that the formation energy of In atom substitution position separated by three atoms is the smallest, and the structure is most easily formed. Under the same doping conditions, the InGaN materials with this structure also have larger band gap and smaller elastic modulus, bulk modulus, shear modulus, and elasticity modulus, which means that its compressive strength and shear stress are slightly weaker, and its toughness and hardness are lower. In addition, the calculation results of phonon spectrum show that the InGaN material with three atoms interval also has good mechanical stability under ambient pressure. This study provides a theoretical basis for studying new hydrogen storage metamaterials with orthorhombic GaN.

Electronic structures and optical properties of intrinsic α-Bi2O3, La-doped, oxygen vacancy doped, and co-doped systems were studied by first-principles method based on density functional theory, in order to obtain α-Bi2O3 photocatalytic materials with excellent performance. The results show that the structure of the doped system is less distorted, and the oxygen vacancy (VO) doped and La-VO co-doped systems have band gaps of both valence band and conduction band shifted down and impurity energy levels introduced in band gaps, indicating that doping can reduce the energy required for electron excitation from valence band to conduction band, which is beneficial to the electron leap. In particular, the La-VO co-doping makes the impurity energy level close to conduction band bottom compared to the oxygen vacancy single doping, and this tendency may make the recombination defect more likely to be the capturing center of photogenerated electrons than the recombination center of photogenerated electron-hole pairs. At the same time, La-VO co-doping leads to the increase of the curvature of band bending near the conduction band bottom, that is, the enhancement of the dispersion relationship, which reduces the effective mass of electrons and accelerates the movement of electrons. Therefore, La-VO co-doping can greatly improve the effective separation of photogenerated electron-hole pairs. On the other hand, La-VO co-doping, while significantly extending the visible light absorption range, also greatly enhances the visible light absorption intensity. Therefore, La-VO co-doping can effectively improve the photocatalytic activity of α-Bi2O3. This study provides a new idea for improving the performance of other photocatalytic materials by using rare earth ion doping.

Electronic structure, hardness and optical properties of four crystal structures of z-BC2N and z-B2CN were studied in this paper by first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). Deep analysis of electronic structure was carried out, indicating that z-BC2N(1) and z-BC2N(2) are indirect and direct wide band gap semiconductor, and band gap are 3.381 eV and 2.449 eV respectively, but z-B2CN(1) and z-B2CN(2) are conductors. Furthermore z-BC2N(1), z-BC2N(2) and z-B2CN(1) are superhard materials. Finally, the optical properties of z-BC2N(1) and z-BC2N(2) were analyzed by calculating the relationship between the basic optical function and photon energy of z-BC2N. Those data indicate that z-BC2N structures can be served as wear-resistant materials and high-temperature-resistant materials that used by control windows.

p-type binary copper oxide semiconductor films were prepared by reactive magnetron sputtering method, and the controlled growth of Cu2O, CuO and Cu4O3 thin films was realized by adjusting the oxygen flow rate. The surface morphology of the films was observed by scanning electron microscopy. Meanwhile, the structure of the films was characterized by X-ray diffractometer and Raman spectroscopy. Measured by UV-Vis spectrophotometer, the band gaps of Cu2O, CuO and Cu4O3 thin films are 2.89 eV, 1.55 eV and 2.74 eV, respectively. In order to further study the surface physical properties of Cu2O, CuO and Cu4O3 thin films, Kelvin probe force microscope (KPFM) was used to directly measure the contact potential difference between film and probe tip (VCPD). The results indicate that the surface work functions of Cu2O, CuO and Cu4O3 thin films gradually decrease with the increase of temperature.

Two one-dimensional coordination polymers were synthesized using rigid organic compound 2-carboxylic acid-4-nitropyridine-1-oxide(POA) as ligand, reacting with rare earth La(III) and Pr(III). The single crystal X-ray diffraction results show that the molecular formula of complex 1 is {［La(POA)3H2O］·CH3OH}n, which belongs to monoclinic system, and the space group is P21/c; with a=1.756 8 nm, b=0.663 6 nm, c=2.048 6 nm, α=90°, β=96.96°, γ=90°, V=2.370 7 nm3, Mr=738.28. The molecular formula of complex 2 is {［Pr(POA)3H2O］·H2O}n, which belongs to monoclinic system, and the space group is P21/c. The cell parameters are a=1.757 8 nm, b=0.656 9 nm, c=2.046 7 nm, α=90°, β=97.20°, γ=90°, V=2.344 8 nm3, Mr=726.25. The composition and structure of coordination units of two complexes are similar, and the central Ln(III) ion is in the coordination environment of a slightly modified tricapped trigonal prism configuration. The properties of two complexes were characterized by infrared, ultraviolet, thermogravimetric analyzer and fluorescence spectrometer. Fluorescence analysis shows that both ligand and complexes have strong fluorescence properties.

In this paper, Sr3ZnNb2O9∶0.3Eu3+, xNa+ (x=0,0.1,0.2,0.3,0.4,0.5) phosphors were successfully prepared by high temperature solid-state reaction. XRD patterns and refinement results show that Eu3+ and Na+ are successfully doped into the matrix and partially substituted Zn2+. The microscopic morphology and element distribution of the samples were confirmed by scanning electron microscopy. The spectral characteristics and thermal stability analysis show that the optimal doping concentration of Na+ is x=0.2. The introduction of Na+ improves the thermal stability of Sr3ZnNb2O9∶0.3Eu3+ phosphors and the calculated activation energy is 0.163 eV. The CIE color coordinate of the Sr3ZnNb2O9∶0.3Eu3+, 0.2Na+ samples is calculated to be (0.618, 0.376), the correlated color temperature and the color purity are 1 855 K and 98.46%, respectively.

Using sodium thiosulfate pentahydrate (Na2S2O3·5H2O), bismuth nitrate pentahydrate (BiN3O9·5H2O) as sulfur source and bismuth source, and urea (CON2H4) as structure guide agent, bismuth sulfide (Bi2S3) with nanorod structure was prepared. It was grown in situ on the cage-like surface of MIL-125(Ti). PEC performance test shows that in 0.5 mol·L-1 sodium sulfate electrolyte (pH=6.0), Bi2S3/MIL-125(Ti)0.07(the addition amount of MIL-125(Ti) is 0.07 g) composite has the highest photoelectric property. The significant enhancement of photoelectric property mainly depends on the bandgap reforming effect of Bi2S3/MIL-125 composite, which significantly improves the absorption capacity of ultraviolet light and visible light. However, due to the slow electron transfer between Bi2S3/MIL-125 photoelectrode and electrolyte interface, in order to improve the interface charge transfer kinetic performance of Bi2S3/MIL-125 photoelectrode, Ag NPs was introduced by thermal reduction method to modify the Bi2S3/MIL-125 photoelectrode. The Ag-Bi2S3/MIL-125 photoelectrode was prepared to accelerate the electron transfer between interfaces. In the range from -0.5 V to -0.8 V (versus Ag/AgCl), maximum saturation photocurrent of Bi2S3/MIL-125(Ti)0.07 (-0.90 mA·cm-2) is about 1.5 times of unmodified Bi2S3(-0.61 mA·cm-2), and maximum saturation photocurrent of Ag-Bi2S3/MIL-125(Ti)0.07 (-1.87 mA·cm-2) is about 3.1 times of unmodified Bi2S3 (-0.61 mA·cm-2).

This paper mainly studies the preparation process of N-type high-efficient crystalline silicon tunnel oxide passivated contact (TOPCon) cells by low pressure chemical vapor deposition (LPCVD) method. The influencing factors of the preparation of tunnel oxide layer and polycrystalline silicon layer by LPCVD were studied and analyzed. The effects of different oxide layer thickness, polysilicon thickness and polysilicon doping amount on the efficiency were studied. The results show that: the thickness of tunneling oxide layer of 1.55 nm shows the best passivation effect; the Voc reaches the highest value when the thickness of polysilicon layer is 120 nm; the Eff reaches the highest when the thickness of polysilicon layer is 90 nm. The field passivation effect of polysilicon layer increases with the increase of P doping concentration. Higher Voc can be obtained when the P doping concentration is 3.0×1015 cm-2.

Two-dimensional transition metal dichalcogenides (TMDs) are a new type of two-dimensional materials after graphene. Due to their unique physical and chemical properties, much attention has been attracted in semiconductors, optoelectronic materials, energy storage, and catalytic hydrogen production. Chemical vapor deposition (CVD) is currently one of the processes suitable for realizing large-scale preparation of two-dimensional materials. Due to the highly controllable parameters of CVD process, it has great advantages in the preparation of two-dimension materials. In this paper, the recent research progress on preparation of TMDs by CVD is reviewed, and the influence of various factors on the growth and final morphology of the products in CVD preparation process, including precursors, temperature, substrate, auxiliaries, pressure and carrier gas are discussed. Some improved CVD processes are listed and their characteristics are also summarized. Finally, challenges and prospects for the development of TMDs prepared by CVD are discussed.

In recent years, as a new visible light responsive nonmetal photocatalyst, graphite-phase carbon nitride (g-C3N4) has been widely used for organic pollutants removal in photocatalysis system due to its suitable band gap width characteristic, enough active sites and low cost. However, the drawback of its low visible-light utilization and fast recombination of photogenerated electron-hole pairs that play negative effect on its photocatalytic activity. Combine with the nonmetal properties of g-C3N4, nonmetal doping is an effective strategy to further improve the photocatalytic performance of g-C3N4, and has attracted more and more attention on photocatalysis. In this paper, the common preparation methods of non metal doped g-C3N4 composite materials are introduced. In addition, the research progress of different nonmetal doped g-C3N4 applied in photocatalytic degradation of organic pollutants is summarized in detail, and its mechanism of photocatalytic degradation of organic pollutants under visible light is also discussed. Finally, the challenges and suggestions for the photocatalytic degradation of organic pollutants in water by nonmetal doped g-C3N4 are proposed, and this review also helps to provide insights into the removal of organic pollutants by nonmetal doped g-C3N4 coupled photocatalysis.