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Development of in situ characterization techniques in molecular beam epitaxy 被引量:1
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作者 Chao Shen Wenkang Zhan +7 位作者 Manyang Li Zhenyu Sun Jian Tang Zhaofeng Wu Chi Xu Bo Xu Chao Zhao Zhanguo Wang 《Journal of Semiconductors》 EI CAS CSCD 2024年第3期9-32,共24页
Ex situ characterization techniques in molecular beam epitaxy(MBE)have inherent limitations,such as being prone to sample contamination and unstable surfaces during sample transfer from the MBE chamber.In recent years... Ex situ characterization techniques in molecular beam epitaxy(MBE)have inherent limitations,such as being prone to sample contamination and unstable surfaces during sample transfer from the MBE chamber.In recent years,the need for improved accuracy and reliability in measurement has driven the increasing adoption of in situ characterization techniques.These techniques,such as reflection high-energy electron diffraction,scanning tunneling microscopy,and X-ray photoelectron spectroscopy,allow direct observation of film growth processes in real time without exposing the sample to air,hence offering insights into the growth mechanisms of epitaxial films with controlled properties.By combining multiple in situ characterization techniques with MBE,researchers can better understand film growth processes,realizing novel materials with customized properties and extensive applications.This review aims to overview the benefits and achievements of in situ characterization techniques in MBE and their applications for material science research.In addition,through further analysis of these techniques regarding their challenges and potential solutions,particularly highlighting the assistance of machine learning to correlate in situ characterization with other material information,we hope to provide a guideline for future efforts in the development of novel monitoring and control schemes for MBE growth processes with improved material properties. 展开更多
关键词 epitaxial growth thin film in situ characterization molecular beam epitaxy(MBE)
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Pit density reduction for AlN epilayers grown by molecular beam epitaxy using Al modulation method
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作者 Huan Liu Peng-Fei Shao +8 位作者 Song-Lin Chen Tao Tao Yu Yan Zi-Li Xie Bin Liu Dun-Jun Chen Hai Lu Rong Zhang Ke Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期95-101,共7页
We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy on AlN/sapphire templates byadopting both the continuous growth method and the Al modulation epitaxy(AME)growth method.The continuous growt... We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy on AlN/sapphire templates byadopting both the continuous growth method and the Al modulation epitaxy(AME)growth method.The continuous growthmethod encounters significant challenges in controlling the growth mode.As the precise Al/N=1.0 ratio is difficult toachieve,either the excessive Al-rich or N-rich growth mode occurs.In contrast,by adopting the AME growth method,sucha difficulty has been effectively overcome.By manipulating the supply time of the Al and nitrogen sources,we were able toproduce AlN films with much improved surface morphology.The first step of the AME method,only supplying Al atoms,is important to wet the surface and the Al adatoms can act as a surfactant.Optimization of the initial Al supply time caneffectively reduce the pit density on the grown AlN surface.The pits density dropped from 12 pits/μm^(2)to 1 pit/μm^(2)andthe surface roughness reduced from 0.72 nm to 0.3 nm in a 2×2μm^(2)area for the AME AlN film homoepitaxially grownon an AlN template. 展开更多
关键词 Al modulation epitaxy molecular beam epitaxy ALN PITS
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Use of the epitaxial MTBs as a 1D gate(Lg=0.4 nm)for the construction of scaling down two-dimensional field-effect transistors
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作者 Youla Yang Daixuan Wu +1 位作者 He Tian Tian-Ling Ren 《Journal of Semiconductors》 EI CAS CSCD 2024年第10期1-2,共2页
In recent years,there has been a significant increase in research focused on the growth of large-area single crystals.Rajan et al.[1]recently achieved the growth of large-area monolayers of transition-metal chalcogeni... In recent years,there has been a significant increase in research focused on the growth of large-area single crystals.Rajan et al.[1]recently achieved the growth of large-area monolayers of transition-metal chalcogenides through assisted nucleation.The quality of molecular beam epitaxy(MBE)-grown two-dimensional(2D)materials can be greatly enhanced by using sacrificial species deposited simultaneously from an electron beam evaporator during the growth process.This technique notably boosts the nucleation rate of the target epitaxial layer,resulting in large,homogeneous monolayers with improved quasiparticle lifetimes and fostering the development of epitaxial van der Waals heterostructures.Additionally,micrometer-sized silver films have been formed at the air-water interface by directly depositing electrospray-generated silver ions onto an aqueous dispersion of reduced graphene oxide under ambient conditions[2]. 展开更多
关键词 silver EPITAXIAL dimensional
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Metal-modulated epitaxy of Mg-doped Al_(0.80)In_(0.20)N-based layer for application as the electron blocking layer in deep ultraviolet light-emitting diodes
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作者 Horacio Irán Solís-Cisneros Carlos Alberto Hernández-Gutiérrez +1 位作者 Enrique Campos-González Máximo López-López 《Journal of Semiconductors》 EI CAS CSCD 2024年第5期80-89,共10页
This work reports the growth and characterization of p-AlInN layers doped with Mg by plasma-assisted molecular beam epitaxy(PAMBE).AlInN was grown with an Al molar fraction of 0.80 by metal-modulated epitaxy(MME)with ... This work reports the growth and characterization of p-AlInN layers doped with Mg by plasma-assisted molecular beam epitaxy(PAMBE).AlInN was grown with an Al molar fraction of 0.80 by metal-modulated epitaxy(MME)with a thickness of 180 nm on Si(111)substrates using AlN as buffer layers.Low substrate temperatures were used to enhance the incorporation of indium atoms into the alloy without clustering,as confirmed by X-ray diffraction(XRD).Cathodoluminescence measurements revealed ultraviolet(UV)range emissions.Meanwhile,Hall effect measurements indicated a maximum hole mobility of 146 cm^(2)/(V∙s),corresponding to a free hole concentration of 1.23×10^(19)cm^(−3).The samples were analyzed by X-ray photoelectron spectroscopy(XPS)estimating the alloy composition and extracting the Fermi level by valence band analysis.Mg-doped AlInN layers were studied for use as the electron-blocking layer(EBL)in LED structures.We varied the Al composition in the EBL from 0.84 to 0.96 molar fraction to assess its theoretical effects on electroluminescence,carrier concentration,and electric field,using SILVACO Atlas.The results from this study highlight the importance and capability of producing high-quality Mg-doped p-AlInN layers through PAMBE.Our simulations suggest that an Al content of 0.86 is optimal for achieving desired outcomes in electroluminescence,carrier concentration,and electric field. 展开更多
关键词 metal-modulated epitaxy ALINN DUV-LED EBL simulation
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Electrical properties and structural optimization of GaN/InGaN/GaN tunnel junctions grown by molecular beam epitaxy
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作者 Jun Fang Fan Zhang +4 位作者 Wenxian Yang Aiqin Tian Jianping Liu Shulong Lu Hui Yang 《Journal of Semiconductors》 EI CAS CSCD 2024年第1期48-54,共7页
The InGaN films and GaN/InGaN/GaN tunnel junctions(TJs)were grown on GaN templates with plasma-assisted molecular beam epitaxy.As the In content increases,the quality of InGaN films grown on GaN templates decreases an... The InGaN films and GaN/InGaN/GaN tunnel junctions(TJs)were grown on GaN templates with plasma-assisted molecular beam epitaxy.As the In content increases,the quality of InGaN films grown on GaN templates decreases and the surface roughness of the samples increases.V-pits and trench defects were not found in the AFM images.p++-GaN/InGaN/n++-GaN TJs were investigated for various In content,InGaN thicknesses and doping concentration in the InGaN insert layer.The InGaN insert layer can promote good interband tunneling in GaN/InGaN/GaN TJ and significantly reduce operating voltage when doping is sufficiently high.The current density increases with increasing In content for the 3 nm InGaN insert layer,which is achieved by reducing the depletion zone width and the height of the potential barrier.At a forward current density of 500 A/cm^(2),the measured voltage was 4.31 V and the differential resistance was measured to be 3.75×10^(−3)Ω·cm^(2)for the device with a 3 nm p++-In_(0.35)Ga_(0.65)N insert layer.When the thickness of the In_(0.35)Ga_(0.65)N layer is closer to the“balanced”thickness,the TJ current density is higher.If the thickness is too high or too low,the width of the depletion zone will increase and the current density will decrease.The undoped InGaN layer has a better performance than n-type doping in the TJ.Polarization-engineered tunnel junctions can enhance the functionality and performance of electronic and optoelectronic devices. 展开更多
关键词 GaN/InGaN/GaN tunnel junctions polarization-engineering molecular beam epitaxy
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Enhanced thermal emission from metal-free,fully epitaxial structures with epsilon-near-zero InAs layers
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作者 Karolis Stašys Andrejus Geižutis Jan Devenson 《Journal of Semiconductors》 EI CAS CSCD 2024年第2期34-39,共6页
We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band... We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band,wide-angle,and p-polarized thermal emission spectra.This approach,employing molecular beam epitaxy,circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths.Our findings contribute a promising route towards simpler,more efficient MIR optoelectronic devices. 展开更多
关键词 epsilon-near-zero thermal emitters indium arsenide LWIR(long wave infraRed) molecular beam epitaxy
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Reshaping Li–Mg hybrid batteries:Epitaxial electrodeposition and spatial confinement on MgMOF substrates via the lattice‐matching strategy
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作者 Yongqin Wang Fulin Cheng +2 位作者 Jiawen Ji Chenyang Cai Yu Fu 《Carbon Energy》 SCIE EI CAS CSCD 2024年第8期248-261,共14页
The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition rem... The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical integration.Herein,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF substrate.The chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial electrocrystallization.Moreover,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular scale.Taking inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF cavities.This innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical kinetics.The resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling performance.Surprisingly,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm^(–2)),maintaining operation for an extended 1200 h,surpassing previously reported benchmarks.Significantly,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallization driven by metal–organic framework(MOF)substrates,paving the way toward the advancement of cuttingedge batteries. 展开更多
关键词 epitaxial electrodeposition lattice‐matching strategy Li-Mg hybrid batteries MOF substrate spatial confinement
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Embedded high-quality ternary GaAs_(1−x)Sb_(x) quantum dots in GaAs nanowires by molecular-beam epitaxy
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作者 Xiyu Hou Lianjun Wen +6 位作者 Fengyue He Ran Zhuo Lei Liu Hailong Wang Qing Zhong Dong Pan Jianhua Zhao 《Journal of Semiconductors》 EI CAS CSCD 2024年第8期18-24,共7页
Semiconductor quantum dots are promising candidates for preparing high-performance single photon sources.A basic requirement for this application is realizing the controlled growth of high-quality semiconductor quantu... Semiconductor quantum dots are promising candidates for preparing high-performance single photon sources.A basic requirement for this application is realizing the controlled growth of high-quality semiconductor quantum dots.Here,we report the growth of embedded GaAs_(1−x)Sb_(x) quantum dots in GaAs nanowires by molecular-beam epitaxy.It is found that the size of the GaAs_(1−x)Sb_(x) quantum dot can be well-defined by the GaAs nanowire.Energy dispersive spectroscopy analyses show that the antimony content x can be up to 0.36 by tuning the growth temperature.All GaAs_(1−x)Sb_(x) quantum dots exhibit a pure zinc-blende phase.In addition,we have developed a new technology to grow GaAs passivation layers on the sidewalls of the GaAs_(1−x)Sb_(x) quantum dots.Different from the traditional growth process of the passivation layer,GaAs passivation layers can be grown simultaneously with the growth of the embedded GaAs_(1−x)Sb_(x) quantum dots.The spontaneous GaAs passivation layer shows a pure zinc-blende phase due to the strict epitaxial relationship between the quantum dot and the passivation layer.The successful fabrication of embedded high-quality GaAs_(1−x)Sb_(x) quantum dots lays the foundation for the realization of GaAs_(1−x)Sb_(x)-based single photon sources. 展开更多
关键词 semiconductor quantum dot NANOWIRE GaAs_(1−x)Sb_(x) molecular-beam epitaxy
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Vapor-Phase Transport Synthesis of MnSAPO-34 and Its Catalytic Properties 被引量:1
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作者 Shao Hui Chen Xia +2 位作者 Wang Binbin Zhong Jing Yang Chao 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2012年第3期68-74,共7页
MnSAPO-34 molecular sieves were synthesized by vapor-phase transport (VPT) method using triethylamine (Et3N) as a structure directing agent (SDA), and were characterized by XRD, BET, SEM, UV-Vis, FT-IR, and TG a... MnSAPO-34 molecular sieves were synthesized by vapor-phase transport (VPT) method using triethylamine (Et3N) as a structure directing agent (SDA), and were characterized by XRD, BET, SEM, UV-Vis, FT-IR, and TG analy- ses. The influence of the zeolite crystallization conditions and the dry-gel composition were investigated. The results showed that the synthesis conditions had an effect on the crystalline phase. Pure MnSAPO-34 had been obtained when it was crystallized at 140 C for 18 hours. The ratio of MnO/A1203 in the starting gel ranging from 0.1 to 0.2 resulted in pure MnSAPO-34 with a CHA topology. Beyond this scope, MnSAPO-5 with an AFI topology structure was obtained as an impurity substance. UV-Vis spectroscopy and FT-IR spectroscopy study indicated that manganese was incorporated into the framework of the molecular sieve. The catalytic performance of MnSAPO-34 molecular sieve was tested by ketalization reaction of l, 2-propanediol with cyclohexanone. High yield of cyclohexanone-1, 2-propanediol ketal was obtained. 展开更多
关键词 MnSAPO-34 vapor-phase transport (VPT) KETALIZATION
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Synthesis of 4-Phenylphthalonitrile by Vapor-Phase Catalytic Ammoxidation of Intermediate 4-Phenyl-<i>o</i>-Tolunitrile: Reaction Kinetics 被引量:3
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作者 G. A. Bagirzade D. B. Tagiyev M. R. Manafov 《Modern Research in Catalysis》 2014年第1期6-11,共6页
Kinetic regularities of 4-phenyl-o-tolunitrile ammoxidation on V-Sb-Bi-Zr/γ-Al2O3 oxide catalyst in the temperature interval 633 - 673 K have been studied. It has been established that rates of conversion of 4-phenyl... Kinetic regularities of 4-phenyl-o-tolunitrile ammoxidation on V-Sb-Bi-Zr/γ-Al2O3 oxide catalyst in the temperature interval 633 - 673 K have been studied. It has been established that rates of conversion of 4-phenyl-o-tolu- nitrile into the aimed 4-phenylphthalonitrile and CO2 are described by half-order equation on concentration of substratum and to be independent of the oxygen and ammonia partial pressures. It has been revealed that formation of 4-phenylphthalimide from byproducts is due to hydrolysis of 4-phenylphthalonitrile;carbon dioxide is produced by oxidation of 4-phenyl-o-tolunitrile and decarboxylation of 4-phenylphthalimide, and 4-phenylben- zonitrile is produced from 4-phenyl-o-tolunitrile and 4-phenylphthalimide. 展开更多
关键词 CATALYTIC AMMOXIDATION Partial Pressures 4-Phenylphthalimide vapor-phase Electron-Donorship Kinetic Measurements
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Epitaxial Properties of Co-Doped ZnO Thin Films Grown by Plasma Assisted Molecular Beam Epitaxy 被引量:1
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作者 曹强 邓江峡 +3 位作者 刘国磊 陈延学 颜世申 梅良模 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第10期2951-2954,共4页
High quality Co-doped ZnO thin films are grown on single crystalline Al2O3(0001) and ZnO(0001) substrates by oxygen plasma assisted molecular beam epitaxy at a relatively lower substrate temperature of 450℃. The ... High quality Co-doped ZnO thin films are grown on single crystalline Al2O3(0001) and ZnO(0001) substrates by oxygen plasma assisted molecular beam epitaxy at a relatively lower substrate temperature of 450℃. The epitaxial conditions are examined with in-situ reflection high energy electron diffraction (RHEED) and ex-situ high resolution x-ray diffraction (HRXRD). The epitaxial thin films are single crystal at film thickness smaller than 500nm and nominal concentration of Co dopant up to 20%. It is indicated that the Co cation is incorporated into the ZnO matrix as Co^2+ substituting Zn^2+ ions. Atomic force microscopy shows smooth surfaces with rms roughness of 1.9 nm. Room-temperature magnetization measurements reveal that the Co-doped ZnO thin films are ferromagnetic with Curie temperatures Tc above room temperature. 展开更多
关键词 coated conductor buffer layer self-epitaxy CEO2
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CeO_2[100]∥MgO[100]in-plane Epitaxy for Bi epitaxial Grain Boundary Junctions
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作者 杨坚 古宏伟 +3 位作者 马平 陈岚峰 常世安 郝建民 《Rare Metals》 SCIE EI CAS CSCD 1997年第2期63-66,共4页
In order to obtain bi epitaxial 45° grain boundary YBa 2Cu 3O 7 (YBCO) junctions, the in plane epitaxy of CeO 2 films on both MgO films and SrTiO 3 substrates was studied. Using magnetron sputtering techni... In order to obtain bi epitaxial 45° grain boundary YBa 2Cu 3O 7 (YBCO) junctions, the in plane epitaxy of CeO 2 films on both MgO films and SrTiO 3 substrates was studied. Using magnetron sputtering technique and decreasing the substrate temperature, 100% CeO 2∥MgO in plane orientation for bi epitaxial grain boundary junction can be obtained. 展开更多
关键词 Josephson junction Bi epitaxial Junction film YBCO
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Epitaxially Grown Ru Clusters-Nickel Nitride Heterostructure Advances Water Electrolysis Kinetics in Alkaline and Seawater Media 被引量:4
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作者 Jiawei Zhu Ruihu Lu +7 位作者 Wenjie Shi Lei Gong Ding Chen Pengyan Wang Lei Chen Jinsong Wu Shichun Mu Yan Zhao 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第2期81-89,共9页
The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conduci... The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conducive to the enhancement of electrocatalytic activity.Herein,theoretical simulations first disclose the charge transfer trend and reinforced inherent electron conduction around the epitaxial heterointerface between Ru clusters and Ni_(3)N substrate(cRu-Ni_(3)N),thus leading to the optimized adsorption behaviors and reduced activation energy barriers.Subsequently,the defectrich nanosheets with the epitaxially grown cRu-Ni_(3)N heterointerface are successfully constructed.Impressively,by virtue of the superiority of intrinsic activity and reaction kinetics,such unique epitaxial heterostructure exhibits remarkable bifunctional catalytic activity toward electrocatalytic OER(226 mV@20 mA cm^(−2))and HER(32 mV@10 mA cm^(−2))in alkaline media.Furthermore,it also shows great application prospect in alkaline freshwater and seawater splitting,as well as solar-to-hydrogen integrated system.This work could provide beneficial enlightenment for the establishment of advanced electrocatalysts with epitaxial heterointerfaces. 展开更多
关键词 alkaline water electrolysis bifunctional electrocatalyst epitaxial heterostructure seawater electrolysis solar-to-hydrogen integrated system
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Rapid epitaxy of 2-inch and high-quality α-Ga_(2)O_(3) films by mist-CVD method 被引量:2
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作者 Xiaojie Wang Wenxiang Mu +4 位作者 Jiahui Xie Jinteng Zhang Yang Li Zhitai Jia Xutang Tao 《Journal of Semiconductors》 EI CAS CSCD 2023年第6期52-58,共7页
High thickness uniformity and large-scale films of α-Ga_(2)O_(3) are crucial factors for the development of power devices.In this work, a high-quality 2-inch α-Ga_(2)O_(3) epitaxial film on c-plane sapphire substrat... High thickness uniformity and large-scale films of α-Ga_(2)O_(3) are crucial factors for the development of power devices.In this work, a high-quality 2-inch α-Ga_(2)O_(3) epitaxial film on c-plane sapphire substrates was prepared by the mist-CVD method.The growth rate and phase control mechanisms were systematically investigated. The growth rate of the α-Ga_(2)O_(3) films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. By adjusting the substrate position(z) from 80 to 50 mm, the growth rate was increased from 307 nm/h to 1.45 μm/h when the growth temperature was fixed at 520 °C.When the growth temperature exceeded 560 °C, ε-Ga_(2)O_(3) was observed to form at the edges of 2-inch sapphire substrate.Phase control was achieved by adjusting the growth temperature. When the growth temperature was 540 °C and the substrate position was 50 mm, the full-width at half maximum(FWHM) of the rocking curves for the(0006) and(10-14) planes were 0.023° and 1.17°. The screw and edge dislocations were 2.3 × 10~6 and 3.9 × 10~(10)cm~(-2), respectively. Furthermore, the bandgaps and optical transmittance of α-Ga_(2)O_(3) films grown under different conditions were characterized utilizing UV-visible and near-IR scanning spectra. 展开更多
关键词 ultra-wide bandgap semiconductor mist-chemical vapor deposition epitaxy alpha-gallium oxide
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Superconductivity in epitaxially grown LaVO_(3)/KTaO_(3)(111)heterostructures 被引量:1
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作者 刘源 刘中然 +3 位作者 张蒙 孙艳秋 田鹤 谢燕武 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期19-24,共6页
Complex oxide heterointerfaces can host a rich of emergent phenomena,and epitaxial growth is usually at the heart of forming these interfaces.Recently,a strong crystalline-orientation-dependent two-dimensional superco... Complex oxide heterointerfaces can host a rich of emergent phenomena,and epitaxial growth is usually at the heart of forming these interfaces.Recently,a strong crystalline-orientation-dependent two-dimensional superconductivity was discovered at interfaces between KTaO_(3)single-crystal substrates and films of other oxides.Unexpectedly,rare of these oxide films was epitaxially grown.Here,we report the existence of superconductivity in epitaxially grown LaVO_(3)/KTaO_(3)(111)heterostructures,with a superconducting transition temperature of~0.5 K.Meanwhile,no superconductivity was detected in the(001)-and(110)-orientated LaVO_(3)/KTaO_(3)heterostructures down to 50 mK.Moreover,we find that for the LaVO_(3)/KTaO_(3)(111)interfaces to be conducting,an oxygen-deficient growth environment and a minimum LaVO_(3)thickness of~0.8 nm(~2 unit cells)are needed. 展开更多
关键词 INTERFACES SUPERCONDUCTIVITY epitaxy
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Review of a direct epitaxial approach to achieving micro-LEDs 被引量:1
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作者 蔡月飞 白洁 王涛 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第1期22-29,共8页
There is a significantly increasing demand of developing augmented reality and virtual reality(AR and VR) devices,where micro-LEDs(μLEDs) with a dimension of ≤ 5 μm are the key elements. Typically, μLEDs are fabri... There is a significantly increasing demand of developing augmented reality and virtual reality(AR and VR) devices,where micro-LEDs(μLEDs) with a dimension of ≤ 5 μm are the key elements. Typically, μLEDs are fabricated by dry-etching technologies, unavoidably leading to a severe degradation in optical performance as a result of dry-etching induced damages. This becomes a particularly severe issue when the dimension of LEDs is ≤ 10 μm. In order to address the fundamental challenge, the Sheffield team has proposed and then developed a direct epitaxial approach to achievingμLEDs, where the dry-etching technologies for the formation of μLED mesas are not needed anymore. This paper provides a review on this technology and then demonstrates a number of monolithically integrated devices on a single chip using this technology. 展开更多
关键词 micro-LED epitaxial growth gallium nitride DISPLAY
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Epitaxial Growth of Si(111)/Er2O3(111)Structure on Si(111)by Molecular Beam Epitaxy
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作者 XU Run TANG Min-Yan +1 位作者 ZHU Yan-Yan WANG Lin-Jun 《Chinese Physics Letters》 SCIE CAS CSCD 2011年第3期176-179,共4页
The Si overlayers are grown by molecular beam epitaxy on atomically smllth Er_(2)O_(3)(111)films prepared on Si(111)substrates.Single crystalline Si overlayers are achieved and are evident due to the spot-like reflect... The Si overlayers are grown by molecular beam epitaxy on atomically smllth Er_(2)O_(3)(111)films prepared on Si(111)substrates.Single crystalline Si overlayers are achieved and are evident due to the spot-like reflective high energy electron diffraction(RHEED)patterns and x-ray diffraction patterns.The epitaxial relationship of the Si overlayer along the surface with respect to the orientation of Er_(2)O_(3)and the Si substrate is as follows:overgrown Si(111)//Er_(2)O_(3)(111)//Si(111).The rough surface of Si overlayers,as identified by both RHEED patterns and atomic force microscopy images,indicates a three-dimensional growth mode.The reason for this is based on the interfacial energy argument.Further growth of Er_(2)O_(3)films on this rough Si overlayer leads to the polycrystalline nature of the topmost Er2O3 layer. 展开更多
关键词 SI(111) epitaxy REFLECTIVE
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Vapor-phase Nitration of Benzene to Nitrobenzene over Supported Sulfuric Acid Catalyst
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作者 Jing Lin CHEN Wei Guo CHENG +2 位作者 Hong Feng LIU Qing Song LIN Lian Hai LU 《Chinese Chemical Letters》 SCIE CAS CSCD 2002年第4期311-314,共4页
Vapor-phase nitration of benzene over solid acid catalyst is expected to be a clean process with no sulfuric acid waste. We investigated this process over solid acidic catalysts utilizing diluted nitric acid (60-70%)... Vapor-phase nitration of benzene over solid acid catalyst is expected to be a clean process with no sulfuric acid waste. We investigated this process over solid acidic catalysts utilizing diluted nitric acid (60-70%) as nitrating agent, and found that supported sulfuric acid catalyst exhibited a very high catalytic activity. Under the conditions of reaction temperature 160-170℃, space velocity (SV) 1200 h-1, the yield and the space-time yield (STY) of nitrobenzene (NB) based on HNO3 were more than 98% and 0.75 kg穔gcat-1穐-1 over 10% H2SO4/SiO2 (by weight) catalyst respectively. 展开更多
关键词 Nitration (vapor-phase) sulfuric acid (supported catalyst) NITROBENZENE
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A first-principles study on remote van der Waals epitaxy through a graphene monolayer on semiconductor substrates
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作者 侯锐 杨身园 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期466-475,共10页
To investigate the mechanism of remote epitaxy, where the overlayer can follow the same crystalline structure as the underlying semiconductor substrate through a thin two-dimensional interlayer, we systematically stud... To investigate the mechanism of remote epitaxy, where the overlayer can follow the same crystalline structure as the underlying semiconductor substrate through a thin two-dimensional interlayer, we systematically study the potential fluctuations of graphene covered Si, Ga As, and Ga N substrates from first-principles. We find that the uneven semiconductor surface, the distorted graphene, and the non-uniform interface charge transfer make significant contributions to the potential fluctuation. The semiconductor substrate with different surface reconstructions and orientations will generate different potential fluctuations through the graphene interlayer. We also calculate and compare the adsorption of adatoms on graphene covered substrates. The adsorption energies of adatoms not only depend on their distances to the underlying semiconductor surface, but are also sensitive to the direction of the charge transfer at the graphene/substrate interface. Changing the semiconductor reconstruction or orientation could even reverse the order of the adsorption energies of cation and anion adatoms by reversing the interface charge transfer direction, leading to a change in the growth orientation of the overlayer.Our study improves the understanding of the mechanism of remote epitaxy, and reveals that it is possible to control the initial nucleation and orientation of overlayers by changing the semiconductor reconstructions and/or orientations in remote epitaxy. 展开更多
关键词 interface ADSORPTION remote epitaxy FIRST-PRINCIPLES
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Intercalation of hafnium oxide between epitaxially-grown monolayer graphene and Ir(111)substrate
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作者 表奕 路红亮 +3 位作者 彭浩 宋志朋 郭辉 林晓 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第9期506-509,共4页
Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we de... Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we demonstrate a successful solution for the intercalation of hafnium oxide into the interface between full-layer graphene and Ir(111)substrate.We first intercalate hafnium atoms beneath the epitaxial graphene.The intercalation of the hafnium atoms leads to the variation of the graphene moire superstructure periodicity,which is characterized by low-energy electron diffraction(LEED)and lowtemperature scanning tunneling microscopy(LT-STM).Subsequently,we introduce oxygen into the interface,resulting in oxidization of the intercalated hafnium.STM and Raman's characterizations reveal that the intercalated hafnium oxide layer could effectively decouple the graphene from the metallic substrate,while the graphene maintains its high quality.Our work suggests a high-k dielectric layer has been successfully intercalated between high-quality epitaxial graphene and metal substrate,providing a platform for applications of large-scale,high-quality graphene for electronic devices. 展开更多
关键词 epitaxial graphene HAFNIUM INTERCALATION OXIDIZATION
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