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Chinese physics B 2021年第1期30卷 398-406页

作者： S K Mitro R Majumder K M Hossain Md Zahid Hasan Md Emran Hossain M A Hadi Bangamata Sheikh Fojilatunnesa Mujib Science and Technology University Jamalpur-2012Bangladesh physics discipline Khulna UniversityKhulna-9208Bangladesh Department of Materials Science and Engineering University of RajshahiRajshahi-6205Bangladesh Department of Electrical and Electronic Engineering International Islamic University ChittagongKumiraChittagong-4318Bangladesh Department of physics University of RajshahiRajshahi6205Bangladesh

We theoretically study the structural, elastic and optical properties of Er Pd Bi together with its anisotropic behaviors using density functional theory. It is observed that Er Pd Bi satisfies the Born stability criteria nicely and possesses high quality of machinability. The anisotropic behavior of Er Pd Bi is reported with the help of theoretical anisotropy indices incorporating 3 D graphical presentation, which suggests that Er Pd Bi is highly anisotropic in nature. It is noticed that the minimum thermal conductivity is very low for Er Pd Bi compared to the several species. This low value of minimum thermal conductivity introduces the potentiality of Er Pd Bi in high-temperature applications such as thermal barrier *** addition, deep optical insights of Er Pd Bi reveal that our material can be used in different optoelectronic and electronic device applications ranging from organic light-emitting diodes, solar panel efficiency, waveguides etc. to integration of integrated circuits. Therefore, we believe that our results will provide a new insight into high-temperature applications and will benefit for the development of promising optoelectric devices as well.

关键词： Er Pd Bi minimum thermal conductivity anisotropy density functional theory(DFT)

Double superlattice structure for improving the performance of ultraviolet light-emitting diodes

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Chinese physics B 2019年第3期28卷 381-385页

作者： Yan-Li Wang Pei-Xian Li Sheng-Rui Xu Xiao-Wei Zhou Xin-Yu Zhang Si-Yu Jiang Ru-Xue Huang Yang Liu Ya-Li Zi Jin-Xing Wu Yue Hao The State Key discipline Laboratory of Wide Band Gap Semiconductor Technology School of Advanced Materials and NanotechnologyXidian University The State Key discipline Laboratory of Wide Band Gap Semiconductor Technology School of MicroelectronicsXidian University

The novel AlGaN-based ultraviolet light-emitting diodes(UV-LEDs) with double superlattice structure(DSL) are proposed and demonstrated by numerical simulation and experimental verification. The DSL consists of 30-period Mg modulation-doped p-AlGaN/u-GaN superlattice(SL) and 4-period p-AlGaN/p-GaN SL electron blocking layer, which are used to replace the p-type GaN layer and electron blocking layer of conventional UV-LEDs, respectively. Due to the special effects and interfacial stress, the AlGaN/GaN short-period superlattice can reduce the acceptor ionization energy of the ptype regions, thereby increasing the hole concentration. Meanwhile, the multi-barrier electron blocking layers are effective in suppressing electron leakage and improving hole injection. Experimental results show that the enhancements of 22.5%and 37.9% in the output power and external quantum efficiency at 120 m A appear in the device with double superlattice structure.

关键词： light-emitting diodes(LEDs) electron blocking layer(EBL) superlattices

Combustion synthesis of Hf-doped zirconolite-rich composite waste forms and the aqueous durability

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先进陶瓷（英文） 2019年第3期8卷 448-455页

作者： Kuibao ZHANG Dan YIN Zongsheng HE Baozhu LUO Haibin ZHANG State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang621010China National Defense Key discipline Lab of Nuclear Waste and Environmental Safety Southwest University of Science and TechnologyMianyang621010China Institute of Nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang621900China

Zirconolite is recognized as one of the most durable waste matrices for the disposal of high-level radioactive wastes(HLWs).In this study,HfO2 was employed as the surrogate of tetravalent ***-bearing zirconolite-based composite waste forms(CaZr1–xHfxTi2O7)were rapidly prepared by combustion synthesis(CS)using CuO as the oxidant,where quick pressing(QP)was introduced to obtain densified *** as solid state reaction process,the Zr site of zirconolite can be totally occupied by Hf(x=1.0)under the CS *** original 2M zirconolite structure was maintained and a small amount of perovskite impurity phase was generated in the final *** aqueous durability of representative sample(Cu-Hf-0.6)was tested,where the 42-day normalized leaching rates(LRi)of Ca,Cu,and Hf are 0.25,3.10×10–2,and 1.11×10–8 g·m–2·d–1.

关键词： combustion synthesis(CS) nuclear waste HfO2 zirconolite aqueous durability

One-step synthesis of novel snowflake-like Si-O/Si-C nanostructures on 3D graphene/Cu foam by chemical vapor deposition

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Nano Research 2018年第4期11卷 1861-1872页

作者： Jing Ning Dong Wang Jincheng Zhang Xin Feng Ruixia Zhong Jiabo Chen Jianguo Dong Lixin Guo Yue Hao The State Key discipline Laboratory of Wide Band Gap Semiconductor Technology Xidian University Xi'an 710071 China ShaanxiJoint Key Laboratory of Graphene Xidian University Xi'an 710071 China School of physics and Optoelectronic Engineering Xidian University Xi'an 710071 China

The recent development of synthesis processes for three-dimensional （3D） graphene-based structures has tended to focus on continuous improvement of porous nanostructures, doping modification during thin-film fabrication, and mechanisms for building 3D architectures. Here, we synthesized novel snowflake- like Si-O/Si-C nanostructures on 3D graphene/Cu foam by one-step low-pressure chemical vapor deposition （CVD）. Through systematic micromorphological characterization, it was determined that the formation mechanism of the nanostructures involved the melting of the Cu foam surface and the subsequent condensation of the resulting vapor, 3D growth of graphene through catalysis in the presence of Cu, and finally , nudeation of the Si-O/Si-C nanostructure in the carbon-rich atmosphere. Thus, by tuning the growth temperature and duration, it should be possible to control the nucleation and evolution of such snowflake-like nanostructures with precision. Electrochemical measurements indicated that the snowflake-like nanostructures showed excellent performance as a material for energy storage. The highest specific capacitance of the Si-O/Si-C nanostructures was - 963.2 mF/cm2 at a scan rate of 1 mV/s. Further, even after 20,000 sequential cycles, the electrode retained 94.4% of its capacitance.

关键词： snowflake-like nanostructures graphene chemical vapor deposition (CVD)

Design of vertical diamond Schottky barrier diode with junction terminal extension structure by using the n-Ga_(2)O_(3)/p-diamond heterojunction

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Chinese physics B 2022年第10期31卷 120-125页

作者： Wang Lin Ting-Ting Wang Qi-Liang Wang Xian-Yi Lv Gen-Zhuang Li Liu-An Li Jin-Ping Ao Guang-Tian Zou State Key Laboratory of Superhard Material College of PhysicsJilin UniversityChangchun 130012China Shenzhen Research Institute Jilin UniversityShenzhen 518057China National Key discipline Laboratory of Wide Bandgap Semiconductor Xidian UniversityXi’an 710071China

A novel junction terminal extension structure is proposed for vertical diamond Schottky barrier diodes(SBDs) by using an n-Ga_(2)O_(3)/p-diamond heterojunction. The depletion region of the heterojunction suppresses part of the forward current conduction path, which slightly increases the on-resistance. On the other hand, the reverse breakdown voltage is enhanced obviously because of attenuated electric field crowding. By optimizing the doping concentration, length, and depth of n-Ga_(2)O_(3), the trade-off between on-resistance and breakdown voltage with a high Baliga figure of merit(FOM)value is realized through Silvaco technology computer-aided design simulation. In addition, the effect of the work functions of the Schottky electrodes is evaluated. The results are beneficial to realizing a high-performance vertical diamond SBD.

关键词： diamond Schottky barrier diode junction terminal extension simulation

Improved crystal quality of GaN film with the in-plane lattice-matched In_(0.17)Al_(0.83)N interlayer grown on sapphire substrate using pulsed metal organic chemical vapor deposition

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Chinese physics B 2014年第6期23卷 478-483页

作者：李亮杨林安薛军帅曹荣涛许晟瑞张进成郝跃 State Key discipline Laboratory of Wide Band Gap Semiconductor Technology School of Microelectronics Xidian University

We report on an improvement in the crystal quality of GaN film with an Ino.17Alo.83N interlayer grown by pulsed metal-organic chemical vapor deposition, which is in-plane lattice-matched to GaN films. The indium composition of about 17% and the reductions of both screw and edge threading dislocations （TDs） in GaN film with the InA1N interlayer are estimated by high resolution X-ray diffraction. Transmission electron microscopy （TEM） measurements are employed to understand the mechanism of reduction in TD density. Raman and photoluminescence measurements indicate that the InA1N interlayer can improve the crystal quality of GaN film, and verify that there is no additional residual stress induced into the GaN film with InA1N interlayer. Atomic force microscopy measurement shows that the InA1N interlayer brings in a smooth surface morphology of GaN film. All the results show that the insertion of the InA1N interlayer is a convenient method to achieve excellent crystal quality in GaN epitaxy.

关键词： In0.17Al0.83N interlayer GaN crystal quality dislocation reduction photoluminescence Raman spectra

Superior material qualities and transport properties of InGaN channel heterostructure grown by pulsed metal organic chemical vapor deposition

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Chinese physics B 2016年第1期25卷 796-801页

作者：张雅超周小伟许晟瑞陈大正王之哲汪星张金风张进成郝跃 State Key discipline Laboratory of Wide Band Gap Semiconductor Technology School of Microelectronics Xidian University

Pulsed metal organic chemical vapor deposition is introduced into the growth of InGaN channel heterostructure for improving material qualities and transport properties. High-resolution transmission electron microscopy imaging shows the phase separation free InGaN channel with smooth and abrupt interface. A very high two-dimensional electron gas density of approximately 1.85 x 10^13 cm-2 is obtained due to the superior carrier confinement. In addition, the Hall mobility reaches 967 cruZ/V-s, owing to the suppression of interface roughness scattering. Furthermore, temperature-dependent Hall measurement results show that InGaN channel heterostructure possesses a steady two-dimensional electron gas density over the tested temperature range, and has superior transport properties at elevated temperatures compared with the traditional GaN channel heterostructure. The gratifying results imply that InGaN channel heterostructure grown by pulsed metal organic chemical vapor deposition is a promising candidate for microwave power devices.

关键词： heterostructure InGaN channel pulsed metal organic chemical vapor deposition

Novel Bianchi VII Space Times and Their Properties

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Journal of Modern physics 2016年第5期7卷 445-457页

作者： Manavendra Mahato Ajay Pratap Singh discipline of physics Indian Institute of Technology Indore Indore India

We construct and investigate non conformal anisotropic Bianchi type VII0 solutions in 5 dimensions. The solutions are asymptotically flat with a singularity. We also construct anisotropic solutions of Einstein-Maxwell gravity using a procedure similar to Majumdar-Papapetrou solutions with various profiles of charged dust and explore ways to hide the singularity behind the horizon. We further embed it in one higher dimension to get an asymptotically anti de Sitter space and approximate two point correlator of operators with higher conformal dimensions by calculating geodesic lengths. We find a peculiar power law decay of the correlator as a function of separation.

关键词： Bianchi Spacetimes Anisotropic Spacetime Gauge/Gravity Correspondence

Enhanced desulfurization performance of hybrid membranes using embedded hierarchical porous SBA-15

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Frontiers of Chemical Science and Engineering 2020年第4期14卷 661-672页

作者： Ye Zhang Jian Song Josue Quispe Mayta Fusheng Pan Xue Ga Mei Li Yimeng Song Meidi Wang Xingzhong Cao Zhongyi Jiang School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Multi-discipline Research Division Institute of High Energy PhysicsChinese Academy of SciencesBejing 100049China

The utilization of materials with a hierarchical porous structure as multi-functional additives is highly attractive in the preparation of hybrid *** this study,novel hybrid membranes are designed by embed-ding hierarchical porous Santa Barbara Amorphous 15(SBA-15)with a dual-pore architecture(micropores and mesopores)for pervaporation *** SBA-15 with cylindrical mesopores provides molecular transport expressways to ensure improved permeability,while micropores on the wall have molecular sieving effects that are essential for the enhancement of permselectivity of thiophene *** thiophene/n-octane mixture as a model system,the hybrid membrane with embedded 6 wt-%SBA-15 exhibits optimal pervaporation desulfurization performance with a permeation flux of 22.07 kg·m^-2·h^-1 and an enrichment factor of ***,the detailed structure and properties of hybrid membranes are systematically *** study demonstrates the immense potential of hierarchical porous materials as additives in membranes to simultaneously increase permeability and permselectivity.

关键词： hybrid membranes hierarchical porous SBA-15 sieving effect pervaporation desulfurization

Growth and Characterization of the Laterally Enlarged Single Crystal Diamond Grown by Microwave Plasma Chemical Vapor Deposition

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Chinese physics Letters 2018年第7期35卷 122-125页

作者：任泽阳张金风张进成许晟瑞张春福苏凯李姚郝跃 State Key discipline Laboratory of Wide Band-Gap Semiconductor Technology School of MicroelectronicsXidian University

Laterally enlarged single crystal diamond is grown on （001） diamond substrates by microwave plasma chemical vapor deposition. Based on the largest side-to-side width of the seed of 7.5 mm, we achieve the as-grown epilayer with the width of about 10mm between the same two sides. The luminescence difference between the broadened part of the single crystal diamond and the vertically epitaxial part is investigated by characterizing the vertical cross section of the sample, and the possible growth mechanism is suggested. Vertical epitaxy on the top （001） surface and lateral growth on the side surfaces occur simultaneously, and thus the growth fronts along the two directions adjoin and form a coalescence zone extending from the edge of the substrate towards the edge of the expanded single crystal diamond top surface. The luminescence intensity of the nitrogen-vacancy center is relatively high in the coalescence zone and a laterally grown part right below, which are attributed mainly to the higher growth rate. However, stress change and crystal quality change are negligible near the coalescence zone.

关键词： Plasma CVD