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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Structural evolution and bandgap modulation of layered β-GeSe2 single crystal under high pressure Hengli Xie(谢恒立), Jiaxiang Wang(王家祥), Lingrui Wang(王玲瑞), Yong Yan(闫勇), Juan Guo(郭娟), Qilong Gao(高其龙), Mingju Chao(晁明举), Erjun Liang(梁二军), and Xiao Ren(任霄) Chin. Phys. B, 2022, 31 (7): 076101.   DOI: 10.1088/1674-1056/ac6db8 Abstract （545）   HTML （20）    PDF （1291KB）（211）       Knowledge map    Germanium diselenide (GeSe2) is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties. However, the evolution of lattice and electronic structure of $β$-GeSe2 at high pressure is still uncertain. Here we prepared high-quality $β$-GeSe2 single crystals by chemical vapor transfer (CVT) technique and performed systematic experimental studies on the evolution of lattice structure and bandgap of $β$-GeSe2 under pressure. High-precision high-pressure ultra low frequency (ULF) Raman scattering and synchrotron angle-dispersive x-ray diffraction (ADXRD) measurements support that no structural phase transition exists under high pressure up to 13.80 GPa, but the structure of $β$-GeSe2 turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa. Two Raman modes keep softening abnormally upon pressure. The bandgap of $β$-GeSe2 reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%, and the sample under pressure performs the piezochromism phenomenon. The bandgap after decompression is smaller than that in the atmospheric pressure environment, which is caused by incomplete recrystallization. These results enrich the insight into the structural and optical properties of $β$-GeSe2 and demonstrate the potential of pressure in modulating the material properties of two-dimensional (2D) Ge-based binary material. Select Radiation effects of electrons on multilayer FePS3 studied with laser plasma accelerator Meng Peng(彭猛), Jun-Bo Yang(杨俊波), Hao Chen(陈浩), Bo-Yuan Li(李博源), Xu-Lei Ge(葛绪雷), Xiao-Hu Yang(杨晓虎), Guo-Bo Zhang(张国博), and Yan-Yun Ma(马燕云) Chin. Phys. B, 2022, 31 (8): 086102.   DOI: 10.1088/1674-1056/ac5c34 Abstract （542）   HTML （0）    PDF （2809KB）（46）       Knowledge map    Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft, but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser-plasma accelerator, we can reproduce exponential energy particle beams as similar as possible to these in space radiation. We used such an electron beam to study the electron radiation effects on the surface structure and performance of two-dimensional material (FePS3). Energetic electron beam led to bulk sample cleavage and damage between areas of uneven thickness. For the FePS3 sheet sample, electron radiation transformed it from crystalline state to amorphous state, causing the sample surface to rough. The full widths at the half maximum of characteristic Raman peaks became larger, and the intensities of characteristic Raman peaks became weak or even disappeared dramatically under electron radiation. This trend became more obvious for thinner samples, and this phenomenon was attributed to the cleavage of P-P and P-S bonds, destabilizing the bipyramid structure of [P2S6]4- unit. The results are of great significance for testing the maximum allowable radiation dose for the two-dimensional material, implying that FePS3 cannot withstand such energetic electron radiation without an essential shield. Select Theoretical and experimental studies on high-power laser-induced thermal blooming effect in chamber with different gases Xiangyizheng Wu(吴祥议政), Jian Xu(徐健), Keling Gong(龚柯菱), Chongfeng Shao(邵崇峰), Yang Kou(寇洋), Yuxuan Zhang(张宇轩), Yong Bo(薄勇), and Qinjun Peng(彭钦军) Chin. Phys. B, 2022, 31 (8): 086105.   DOI: 10.1088/1674-1056/ac6165 Abstract （436）   HTML （0）    PDF （1981KB）（189）       Knowledge map    High-power laser induced thermal blooming effects in a closed chamber with three different gases are investigated theoretically and experimentally in this work. In the theoretical treatment, an incompressible gas turbulent model is adopted. In the numerical simulation the gas refractive index as a function of both the temperature and pressure is taken into consideration. In the experimental study the pump-probe technology is adopted. A high-power 1064-nm fiber laser with maximum output power of 12 kW is used to drive the gas thermal blooming, and a 50-mW high-beam-quality 637-nm laser diode (LD) is used as a probe beam. The influences of the gas thermal blooming in the chamber on the probe beam wavefront and beam quality are analyzed for three different gases of air, nitrogen, and helium, respectively. The results indicate that nitrogen is well suitable for restraining thermal blooming effect for high-power laser. The measured data are in good agreement with the simulated results. Select Microstructure and hardening effect of pure tungsten and ZrO2 strengthened tungsten under carbon ion irradiation at 700℃ Chun-Yang Luo(罗春阳), Bo Cui(崔博), Liu-Jie Xu(徐流杰), Le Zong(宗乐), Chuan Xu(徐川), En-Gang Fu(付恩刚), Xiao-Song Zhou(周晓松), Xing-Gui Long(龙兴贵), Shu-Ming Peng(彭述明), Shi-Zhong Wei(魏世忠), and Hua-Hai Shen(申华海) Chin. Phys. B, 2022, 31 (9): 096102.   DOI: 10.1088/1674-1056/ac6b25 Abstract （377）   HTML （0）    PDF （6200KB）（69）       Knowledge map    Microstructure evolution and hardening effect of pure tungsten and W-1.5%ZrO2 alloy under carbon ion irradiation are investigated by using transmission electron microscopy and nano-indentation. Carbon ion irradiation is performed at 700 ℃ with irradiation damages ranging from 0.25 dpa to 2.0 dpa. The results show that the irradiation defect clusters are mainly in the form of dislocation loop. The size and density of dislocation loops increase with irradiation damages intensifying. The W-1.5%ZrO2 alloy has a smaller dislocation loop size than that of pure tungsten. It is proposed that the phase boundaries have the ability to absorb and annihilate defects and the addition of ZrO2 phase improves the sink strength for irradiation defects. It is confirmed that the W-1.5%ZrO2 alloy shows a smaller change in hardness than the pure tungsten after being irradiated. From the above results, we conclude that the addition of ZrO2 into tungsten can significantly reduce the accumulation of irradiated defects and improve the irradiation resistance behaviors of the tungsten materials. Select Structural evolution and molecular dissociation of H2S under high pressures Wen-Ji Shen(沈文吉), Tian-Xiao Liang(梁天笑), Zhao Liu(刘召), Xin Wang(王鑫), De-Fang Duan(段德芳), Hong-Yu Yu(于洪雨), and Tian Cui(崔田) Chin. Phys. B, 2022, 31 (7): 076102.   DOI: 10.1088/1674-1056/ac5980 Abstract （365）   HTML （4）    PDF （1912KB）（81）       Knowledge map    Solid H$_{2}$S as the precursor for H$_{3}$S with incredible superconducting properties under high pressure, has recently attracted extensive attention. Here in this work, we propose two new phases of H$_{2}$S with $P$4$_{2}/n$ and $I$4$_{1}/a$ lattice symmetries in a pressure range of 0 GPa-30 GPa through first-principles structural searches, which complement the phase transition sequence. Further an $ab initio$ molecular dynamics simulation confirms that the molecular phase $P2/c$ of H$_{2}$S is gradually dissociated with the pressure increasing and reconstructs into a new $P$2$_{1}/m$ structure at 160 GPa, exhibiting the superconductivity with $T_{\rm c}$ of 82.5 K. Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H$_{2}$S. Select First-principles study of a new BP2 two-dimensional material Zhizheng Gu(顾志政), Shuang Yu(于爽), Zhirong Xu(徐知荣), Qi Wang(王琪), Tianxiang Duan(段天祥), Xinxin Wang(王鑫鑫), Shijie Liu(刘世杰), Hui Wang(王辉), and Hui Du(杜慧) Chin. Phys. B, 2022, 31 (8): 086107.   DOI: 10.1088/1674-1056/ac5a40 Abstract （353）   HTML （1）    PDF （1193KB）（156）       Knowledge map    Two-dimensional materials have a wide range of applications in many aspects due to their unique properties. Here we carry out a detailed structural search and design of the BP2 using the first principles method, and find a new PMM2 sheet. The analysis of the phonon dispersive curves shows that the 2D PMM2 is dynamic stable. The study of molecular dynamics shows that the 2D PMM2 can be stable under high temperature, even at 600 K. Most importantly, when a suitable strain is applied, the structure can exhibit other electronic properties such as direct band gap semiconductor. In addition, the small strain can tune the band gap value of the PMM2 structure to around 1.4 eV, which is very close to the ideal band gap of solar materials. Therefore, the 2D PMM2 may have potential applications in the field of photovoltaic materials. Select Tunable anharmonicity versus high-performance thermoelectrics and permeation in multilayer (GaN)1-x(ZnO)x Hanpu Liang(梁汉普) and Yifeng Duan(段益峰) Chin. Phys. B, 2022, 31 (7): 076301.   DOI: 10.1088/1674-1056/ac5c38 Abstract （350）   HTML （4）    PDF （7464KB）（94）       Knowledge map    Nonisovalent (GaN)$_{1-x}$(ZnO)$_x$ alloys are more technologically promising than their binary counterparts because of the abruptly reduced band gap. Unfortunately, the lack of two-dimensional (2D) configurations as well as complete stoichiometries hinders to further explore the thermal transport, thermoelectrics, and adsorption/permeation. We identify that multilayer (GaN)$_{1-x}$(ZnO)$_x$ stabilize as wurtzite-like $Pm$-(GaN)$_3$(ZnO)$_1$, $Pmc2_1$-(GaN)$_1$(ZnO)$_1$, $P3m1$-(GaN)$_1$(ZnO)$_2$, and haeckelite $C2/m$-(GaN)$_1$(ZnO)$_3$ via structural searches. $P3m1$-(GaN)$_1$(ZnO)$_2$ shares the excellent thermoelectrics with the figure of merit $ZT$ as high as 3.08 at 900 K for the p-type doping due to the ultralow lattice thermal conductivity, which mainly arises from the strong anharmonicity by the interlayer asymmetrical charge distributions. The $p$-$d$ coupling is prohibited from the group theory in $C2/m$-(GaN)$_1$(ZnO)$_3$, which thereby results in the anomalous band structure versus ZnO composition. To unveil the adsorption/permeation of H$^+$, Na$^+$, and OH$^-$ ions in $AA$-stacking configurations, the potential wells and barriers are explored from the Coulomb interaction and the ionic size. Our work is helpful in experimental fabrication of novel optoelectronic and thermoelectric devices by 2D (GaN)$_{1-x}$(ZnO)$_x$ alloys. Select Synthesis of hexagonal boron nitride films by dual temperature zone low-pressure chemical vapor deposition Zhi-Fu Zhu(朱志甫), Shao-Tang Wang(王少堂), Ji-Jun Zou(邹继军), He Huang(黄河), Zhi-Jia Sun(孙志嘉), Qing-Lei Xiu(修青磊), Zhong-Ming Zhang(张忠铭), Xiu-Ping Yue(岳秀萍), Yang Zhang(张洋), Jin-Hui Qu(瞿金辉), and Yong Gan(甘勇) Chin. Phys. B, 2022, 31 (8): 086103.   DOI: 10.1088/1674-1056/ac657d Abstract （347）   HTML （1）    PDF （2178KB）（86）       Knowledge map    Hexagonal boron nitride (h-BN) films are synthesized by dual temperature zone low-pressure chemical vapor deposition (LPCVD) through using a single ammonia borane precursor on non-catalytic c-plane Al2O3 substrates. The grown films are confirmed to be h-BN films by various characterization methods. Meanwhile, the growth rates and crystal quality of h-BN films at different positions in the dual temperature zone are studied. It is found that the growth rates and crystal quality of the h-BN films at different positions on the substrate are significantly different. The growth rates of the h-BN thin films show their decreasing trends with the rearward position, while the crystal quality is improved. This work provides an experimental basis for the preparation of large area wafer thick h-BN films by LPCVD. Select Influence of particle size on the breaking of aluminum particle shells Tian-Yi Wang(王天一), Zheng-Qing Zhou(周正青), Jian-Ping Peng(彭剑平),Yu-Kun Gao(高玉坤), and Ying-Hua Zhang(张英华) Chin. Phys. B, 2022, 31 (7): 076107.   DOI: 10.1088/1674-1056/ac5615 Abstract （336）   HTML （0）    PDF （2666KB）（86）       Knowledge map    Rupturing the alumina shell (shell-breaking) is a prerequisite for releasing energy from aluminum powder. Thermal stress overload in a high-temperature environment is an important factor in the rupture of the alumina shell. COMSOL Multiphysics was used to simulate and analyze the shell-breaking response of micron-scale aluminum particles with different particle sizes at 650 ℃ in vacuum. The simulation results show that the thermal stability time and shell-breaking response time of 10 μm-100 μm aluminum particles are 0.15 μs-11.44 μs and 0.08 μs-3.94 μs, respectively. They also reveal the direct causes of shell breaking for aluminum particles with different particle sizes. When the particle size is less than 80 μm, the shell-breaking response is a direct result of compressive stress overload. When the particle size is between 80 μm and 100 μm, the shell-breaking response is a direct result of tensile stress overload. This article provides useful guidance for research into the energy release of aluminum powder. Select High-pressure new phases of V-N compounds Xu-Han Shi(时旭含), Zhi-Hui Li(李志慧), Yuanyuan Liu(刘媛媛), Yuanyuan Wang(王元元), Ran Liu(刘冉), Kuo Hu(胡阔), and Zhen Yao(姚震) Chin. Phys. B, 2023, 32 (5): 056103.   DOI: 10.1088/1674-1056/acbc6d Abstract （331）   HTML （6）    PDF （2096KB）（240）       Knowledge map    The high-pressure diagram of V-N compounds is enriched by proposed seven new stable high-pressure phases. The $P$-1-VN$_{4}$ with the armchair N-rich structure may be quenched to ambient conditions. The formed N-N covalent bond plays an important role for the structural stability of N-chain. The charge transfer results in a V-N ionic bond interaction, which further improves the stability of N-chain structure. The $P$-1-VN$_{4}$, $P4mnc$-VN$_{8}$, and $Immm$-VN$_{10}$ with the outstanding detonation properties have potential application in explosive field. Select Porous AlN films grown on C-face SiC by hydride vapor phase epitaxy Jiafan Chen(陈家凡), Jun Huang(黄俊), Didi Li(李迪迪), and Ke Xu(徐科) Chin. Phys. B, 2022, 31 (7): 076802.   DOI: 10.1088/1674-1056/ac597e Abstract （327）   HTML （0）    PDF （2644KB）（74）       Knowledge map    We report the growth of porous AlN films on C-face SiC substrates by hydride vapor phase epitaxy (HVPE). The influences of growth condition on surface morphology, residual strain and crystalline quality of AlN films have been investigated. With the increase of the V/III ratio, the growth mode of AlN grown on C-face 6H-SiC substrates changes from step-flow to pit-hole morphology. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman analysis show that cracks appear due to tensile stress in the films with the lowest V/III ratio and the highest V/III ratio with a thickness of about 3 μm. In contrast, under the medium V/III ratio growth condition, the porous film can be obtained. Even when the thickness of the porous AlN film is further increased to 8 μm, the film remains porous and crack-free, and the crystal quality is improved. Select Theoretical and experimental study of phase optimization of tapping mode atomic force microscope Zheng Wei(魏征), An-Jie Peng(彭安杰), Feng-Jiao Bin(宾凤姣), Ya-Xin Chen(陈亚鑫), and Rui Guan(关睿) Chin. Phys. B, 2022, 31 (7): 076801.   DOI: 10.1088/1674-1056/ac4a6d Abstract （325）   HTML （4）    PDF （1919KB）（54）       Knowledge map    Phase image in tapping-mode atomic force microscope (TM-AFM) results from various dissipations in a microcantilever system. The phases mainly reflect the tip-sample contact dissipations which allow the nanoscale characteristics to be distinguished from each other. In this work, two factors affecting the phase and phase contrast are analyzed. It is concluded from the theoretical and experimental results that the phases and phase contrasts in the TM-AFM are related to the excitation frequency and energy dissipation of the system. For a two-component blend, it is theoretically and experimentally proven that there exists an optimal excitation frequency for maximizing the phase contrast. Therefore, selecting the optimal excitation frequency can potentially improve the phase contrast results. In addition, only the key dissipation between the tip and sample is found to accurately reflect the sample properties. Meanwhile, the background dissipation can potentially reduce the contrasts of the phase images and even mask or distort the effective information in the phase images. In order to address the aforementioned issues, a self-excited method is adopted in this study in order to eliminate the effects of the background dissipation on the phases. Subsequently, the real phase information of the samples is successfully obtained. It is shown in this study that the eliminating of the background dissipation can effectively improve the phase contrast results and the real phase information of the samples is accurately reflected. These results are of great significance in optimizing the phases of two-component samples and multi-component samples in atomic force microscope. Select Heterogeneous integration of GaSb layer on (100) Si substrate by ion-slicing technique Ren-Jie Liu(刘仁杰), Jia-Jie Lin(林家杰), Zheng-Hao Shen(沈正皓), Jia-Liang Sun(孙嘉良), Tian-Gui You(游天桂), Jin Li(李进), Min Liao(廖敏), and Yi-Chun Zhou(周益春) Chin. Phys. B, 2022, 31 (7): 076103.   DOI: 10.1088/1674-1056/ac5605 Abstract （323）   HTML （0）    PDF （1957KB）（126）       Knowledge map    Integration of the high-quality GaSb layer on an Si substrate is significant to improve the GaSb application in optoelectronic integration. In this work, a suitable ion implantation fluence of 5×1016-cm-2 H ions for GaSb layer transfer is confirmed. Combining the strain change and the defect evolution, the blistering and exfoliation processes of GaSb during annealing is revealed in detail. With the direct wafer bonding, the GaSb layer is successfully transferred onto a (100) Si substrate covered by 500-nm thickness thermal oxide SiO2 layer. After being annealed at 200 ℃, the GaSb layer shows high crystalline quality with only 77 arcsec for the full width at half maximum (FWHM) of the x-ray rocking curve (XRC). Select Molecular dynamics simulation of interaction between nanorod and phospholipid molecules bilayer Xin Wang(王鑫), Xiang-Qin Li(李香琴), Tian-Qing Liu(刘天庆), Li-Dan Zhao(赵丽丹), Ke-Dong Song(宋克东), and Dan Ge(葛丹) Chin. Phys. B, 2023, 32 (1): 016201.   DOI: 10.1088/1674-1056/ac6ed8 Abstract （321）   HTML （2）    PDF （4304KB）（156）       Knowledge map    Natural and artificially prepared nanorods' surfaces have proved to have good bactericidal effect and self-cleaning property. In order to investigate whether nanorods can kill the enveloped virus, like destroying bacterial cell, we study the interaction between nanorods and virus envelope by establishing the models of nanorods with different sizes as well as the planar membrane and vesicle under the Dry Martini force field of molecular dynamics simulation. The results show that owing to the van der Waals attraction between nanorods and the tail hydrocarbon chain groups of phospholipid molecules, the phospholipid molecules on virus envelope are adsorbed to nanorods on a large scale. This process will increase the surface tension of lipid membrane and reduce the order of lipid molecules, resulting in irreparable damage to planar lipid membrane. Nanorods with different diameters have different effects on vesicle envelope, the larger the diameter of nanorod, the weaker the van der Waals effect on the unit cross-sectional area is and the smaller the degree of vesicle deformation. There is synergy between the nanorods in the nanorod array, which can enhance the speed and scale of lipid adsorption. The vesicle adsorbed in the array are difficult to desorb, and even if desorbed, vesicle will be seriously damaged. The deformation rate of the vesicle adsorbed in the nanorod array exceeds 100%, implying that the nanorod array has a strong destructive effect on the vesicle. This preliminarily proves the feasibility of nanorod array on a surface against enveloped virus, and provides a reference for the design of corresponding nanorods surface. Select Effect of spatial heterogeneity on level of rejuvenation in Ni80P20 metallic glass Tzu-Chia Chen, Mahyuddin KM Nasution, Abdullah Hasan Jabbar, Sarah Jawad Shoja, Waluyo Adi Siswanto, Sigiet Haryo Pranoto, Dmitry Bokov, Rustem Magizov, Yasser Fakri Mustafa, A. Surendar, Rustem Zalilov, Alexandr Sviderskiy, Alla Vorobeva, Dmitry Vorobyev, and Ahmed Alkhayyat Chin. Phys. B, 2022, 31 (9): 096401.   DOI: 10.1088/1674-1056/ac615e Abstract （318）   HTML （1）    PDF （7014KB）（63）       Knowledge map    Understanding the relation between spatial heterogeneity and structural rejuvenation is one of the hottest topics in the field of metallic glasses (MGs). In this work, molecular dynamics (MD) simulation is implemented to discover the effects of initial spatial heterogeneity on the level of rejuvenation in the Ni$_{80}$P$_{20 }$MGs. For this purpose, the samples are prepared with cooling rates of $10^{10}$ K/s-$10^{12}$ K/s to make glassy alloys with different atomic configurations. Firstly, it is found that the increase in the cooling rate leads the Gaussian-type shear modulus distribution to widen, indicating the aggregations in both elastically soft and hard regions. After the primary evaluations, the elastostatic loading is also used to transform structural rejuvenation into the atomic configurations. The results indicate that the sample with intermediate structural heterogeneity prepared with 10$^{11}$ K/s exhibits the maximum structural rejuvenation which is due to the fact that the atomic configuration in an intermediate structure contains more potential sites for generating the maximum atomic rearrangement and loosely packed regions under an external excitation. The features of atomic rearrangement and structural changes under the rejuvenation process are discussed in detail. Select In situ study of calcite-III dimorphism using dynamic diamond anvil cell Xia Zhao(赵霞), Sheng-Hua Mei(梅升华), Zhi Zheng(郑直), Yue Gao(高悦), Jiang-Zhi Chen(陈姜智), Yue-Gao Liu(刘月高), Jian-Guo Sun(孙建国), Yan Li(李艳), and Jian-Hui Sun(孙建辉) Chin. Phys. B, 2022, 31 (9): 096201.   DOI: 10.1088/1674-1056/ac6157 Abstract （313）   HTML （0）    PDF （1343KB）（66）       Knowledge map    The phase transitions among the high-pressure polymorphic forms of CaCO3 (cc-I, cc-II, cc-III, and cc-IIIb) are investigated by dynamic diamond anvil cell (dDAC) and in situ Raman spectroscopy. Experiments are carried out at room temperature and high pressures up to 12.8 GPa with the pressurizing rate varying from 0.006 GPa/s to 0.056 GPa/s. In situ observation shows that with the increase of pressure, calcite transforms from cc-I to cc-II at ～ 1.5 GPa and from cc-II to cc-III at ～ 2.5 GPa, and transitions are independent of the pressurizing rate. Further, as the pressure continues to increase, the cc-IIIb begins to appear and coexists with cc-III within a pressure range that is inversely proportional to the pressurizing rate. At the pressurizing rates of 0.006, 0.012, 0.021, and 0.056 GPa/s, the coexistence pressure ranges of cc-III and cc-IIIb are 2.8 GPa-9.8 GPa, 3.1 GPa-6.9 GPa, 2.7 GPa-6.0 GPa, and 2.8 GPa-4.5 GPa, respectively. The dependence of the coexistence on the pressurizing rate may result from the influence of pressurizing rate on the activation process of transition by reducing the energy barrier. The higher the pressurizing rate, the lower the energy barrier is, and the easier it is to pull the system out of the coexistence state. The results of this in situ study provide new insights into the understanding of the phase transition of calcite. Select Introducing voids around the interlayer of AlN by high temperature annealing Jianwei Ben(贲建伟), Jiangliu Luo(罗江流), Zhichen Lin(林之晨), Xiaojuan Sun(孙晓娟), Xinke Liu(刘新科), and Xiaohua Li(黎晓华) Chin. Phys. B, 2022, 31 (7): 076104.   DOI: 10.1088/1674-1056/ac3d7f Abstract （313）   HTML （1）    PDF （1712KB）（33）       Knowledge map    Introducing voids into AlN layer at a certain height using a simple method is meaningful but challenging. In this work, the AlN/sapphire template with AlN interlayer structure was designed and grown by metal-organic chemical vapor deposition. Then, the AlN template was annealed at 1700 ℃ for an hour to introduce the voids. It was found that voids were formed in the AlN layer after high-temperature annealing and they were mainly distributed around the AlN interlayer. Meanwhile, the dislocation density of the AlN template decreased from 5.26×109 cm-2 to 5.10×108 cm-2. This work provides a possible method to introduce voids into AlN layer at a designated height, which will benefit the design of AlN-based devices. Select Angular dependence of proton-induced single event transient in silicon-germanium heterojunction bipolar transistors Jianan Wei(魏佳男), Yang Li(李洋), Wenlong Liao(廖文龙), Fang Liu(刘方), Yonghong Li(李永宏), Jiancheng Liu(刘建成), Chaohui He(贺朝会), and Gang Guo(郭刚) Chin. Phys. B, 2022, 31 (8): 086106.   DOI: 10.1088/1674-1056/ac5d32 Abstract （312）   HTML （1）    PDF （1146KB）（99）       Knowledge map    We investigate the angular dependence of proton-induced single event transient (SET) in silicon-germanium heterojunction bipolar transistors. Experimental results show that the overall SET cross section is almost independent of proton incident angle. However, the proportion of SET events with long duration and high integral charge collection grows significantly with the increasing angle. Monte Carlo simulations demonstrate that the integral cross section of proton incident events with high ionizing energy deposition in the sensitive volume tends to be higher at larger incident angles, which is associated with the angular distribution of proton-induced secondary particles and the geometry of sensitive volume. Select First-principles study on β-GeS monolayer as high performance electrode material for alkali metal ion batteries Meiqian Wan(万美茜), Zhongyong Zhang(张忠勇), Shangquan Zhao(赵尚泉)†, and Naigen Zhou(周耐根)‡ Chin. Phys. B, 2022, 31 (9): 096301.   DOI: 10.1088/1674-1056/ac5d2e Abstract （309）   HTML （0）    PDF （1835KB）（138）       Knowledge map    Based on the density functional theory calculations, we have investigated the feasibility of two-dimensional β-GeS monolayer as high-performance anodes for alkali metal ion batteries. The results show that the electrical conductivity of β-GeS monolayer can be enhanced after adsorbing the alkali metal atoms owing to the semiconductor-to-metal transition. The low diffusion barriers of alkali metal atoms on the β-GeS surface indicate a rapid charge/discharge rate without metal clustering. Moreover, the low average open-circuit voltage (0.211 V) and a high theoretical capacity (1024 mAh·g-1) for Na suggest that the β-GeS monolayer is a promising anode material for Na-ion batteries with high performance. Select Pressure-induced novel structure with graphene-like boron-layer in titanium monoboride Yuan-Yuan Jin(金园园), Jin-Quan Zhang(张金权), Shan Ling(凌山), Yan-Qi Wang(王妍琪), Song Li(李松), Fang-Guang Kuang(匡芳光), Zhi-Yan Wu(武志燕), and Chuan-Zhao Zhang(张传钊) Chin. Phys. B, 2022, 31 (11): 116104.   DOI: 10.1088/1674-1056/ac9222 Abstract （309）   HTML （0）    PDF （1275KB）（90）       Knowledge map    The recent discovery of the novel boron-framework in boron-rich metal borides with complex structures and intriguing features under high pressure has stimulated the search into the unique boron-network in the metal monoborides or boron-deficient metal borides at high pressure. Herein, based on the particle swarm optimization algorithm combined with first-principles calculations, we thoroughly explored the structural evolution and properties of TiB up to 200 GPa. This material undergoes a pressure-induced phase transition of $Pnma$ $\to $ $Cmcm$ $\to $ $Pmmm$. Besides of two known phases $Pnma$ and $Cmcm$, an unexpected orthorhombic $Pmmm$ structure was predicted to be energetically favored in the pressure range of 110.88-200 GPa. Intriguingly, the B covalent network eventually evolved from a one-dimensional zigzag chain in $Pnma$-TiB and $Cmcm$-TiB to a graphene-like B-sheet in $Pmmm$-TiB. On the basis of the microscopic hardness model, the calculated hardness ($H_{\rm v}$) values of $Pnma$ at 1 atm, $Cmcm$ at 100 GPa, and $Pmmm$ at 140 GPa are 36.81 GPa, 25.17 GPa, and 15.36 GPa, respectively. Remarkably, analyses of the density of states, electron localization function and the crystal orbital Hamilton population (COHP) exhibit that the bonding nature in the three TiB structures can be considered as a combination of the B-B and Ti-B covalent interactions. Moreover, the high hardness and excellent mechanical properties of the three TiB polymorphs can be ascribed to the strong B-B and Ti-B covalent bonds. page Page 1 of 6 Total 118 records First page Prev page Next page Last page