Considering two beams propagate in semiconductor crystal, this paper discusses the polarization dependence of pump beam-induced intensity attenuation of probe beam due to two-photon absorption （TPA）. Numerical calcu...Considering two beams propagate in semiconductor crystal, this paper discusses the polarization dependence of pump beam-induced intensity attenuation of probe beam due to two-photon absorption （TPA）. Numerical calculation and experimental measurement demonstrate that TPA coefficient is polarization dependent. For homogeneous materials, probe beam attenuation arises from the imaginary part of diagonal and off-diagonal components of third-order nonlinear susceptibilities.展开更多
Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are pr...Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are promising candidates for realizing high-performance photodetectors. Here, after a brief resume of photodetector performance parameters and operation mechanisms, we review the recent advancements in application of SMOSCs as photodetectors, including photoconductors, phototransistors, and photodiodes. More importantly, the SMOSC-based photodetectors are further categorized according to their detection regions that cover a wide range from ultraviolet to near infrared. Finally, challenges and outlooks of SMOSC-based photodetectors are provided.展开更多
Owing to enhanced charge transport efficiency arising from the ultrathin nature,two-dimensional(2D)organic semiconductor single crystals(OSSCs)are emerging as a fascinating platform for high-performance organic field-...Owing to enhanced charge transport efficiency arising from the ultrathin nature,two-dimensional(2D)organic semiconductor single crystals(OSSCs)are emerging as a fascinating platform for high-performance organic field-effect transistors(OFETs).However,ucoffee-ring"effect induced by an evaporation-induced convective flow near the contact line hinders the large-area growth of 2D OSSCs through a solution process.Here,we develop a new strategy of suppressing the"coffee-ring"effect by using an organic semiconductor:polymer blend solution.With the high-viscosity polymer in the organic solution,the evaporation-induced flow is remarkably weakened,ensuring the uniform molecule spreading for the 2D growth of the OSSCs.As an example,wafer-scale growth of crystalline film consisting of few-layered 2,7-didecylbenzothienobenzothiophene(C10-BTBT)crystals was successfully accomplished via blade coating.OFETs based on the crystalline film exhibited a maximum hole mobility up to 12.6 cm^2·V^-1·s^-1,along with an average hole mobility as high as 8.2 cm^2·V^-1·s^-1.Our work provides a promising strategy for the large-area growth of 2D OSSCs toward high-performance organic electronics.展开更多
The tunable terahertz（THz） filter has been designed and studied, which is composed of 1D photonic crystal（PC） containing a defect layer of semiconductor Ga As. The analytical solution of 1D defective PC（1DDPC） i...The tunable terahertz（THz） filter has been designed and studied, which is composed of 1D photonic crystal（PC） containing a defect layer of semiconductor Ga As. The analytical solution of 1D defective PC（1DDPC） is deduced based on the transfer matrix method, and the electromagnetic plane wave numerical simulation of this 1DDPC is performed by using the finite element method. The calculated and simulated results have confirmed that the filtering transmittance of this 1DDPC in symmetric structure of air/（Si/SiO_2）~N/GaAs/（SiO_2/Si）~N/air is far higher than in asymmetric structure of air/（Si/SiO_2）~N/GaAs/（Si/SiO_2）~N/air, where the filtering frequency can be tuned by the external pressure. It can provide a feasible route to design the external pressure-controlled THz filter based on 1DPC with a defective semiconductor.展开更多
By combing artificial micro–nano structures, photonic crystals（PCs）, with traditional semiconductor laser material to realize the dynamic collaborative control of photonic states and confined electrons, the band en...By combing artificial micro–nano structures, photonic crystals（PCs）, with traditional semiconductor laser material to realize the dynamic collaborative control of photonic states and confined electrons, the band engineering of the PC has been confirmed. This brings new development space for the semiconductor laser, such as for low threshold and high efficiency.Based on a series of works by Zheng＇s group, this paper has reviewed kinds of PC lasers including electrical injection PC vertical cavity and lateral cavity surface-emitting lasers, and PC high beam quality lasers, to show that the PC is vital for promoting the continuous improvement of semiconductor laser performance at present and in the future.展开更多
We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement...We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement of probes. The final expressions for identifying the electrical conductivity are presented in the form of a series of analytic functions. The suggested method is experimentally verified, and practical recommendations of how to apply it are also provided.展开更多
Photonic crystals(PCs) have attracted much considerable research attention in the past two decades. They are artificially fabricated periodic dielectric structures. The periodic dielectric structures have photonic ban...Photonic crystals(PCs) have attracted much considerable research attention in the past two decades. They are artificially fabricated periodic dielectric structures. The periodic dielectric structures have photonic band gap(PBG) and are referred to as photonic band gap materials. This paper mainly introduces one-dimensional (1-D) and 2D PCs applied in the semiconductor lasers.展开更多
Using tellurium as a solvent, we grew ZnTe ingots of 30 mm in diameter and 70 mm in length by a temperature gradient solution growth method. Hall tests conducted at 300 K indicated that the as-grown ZnTe exhibits p-ty...Using tellurium as a solvent, we grew ZnTe ingots of 30 mm in diameter and 70 mm in length by a temperature gradient solution growth method. Hall tests conducted at 300 K indicated that the as-grown ZnTe exhibits p-type conductivity, with a carrier concentration of approximately 10^14cm^-3, a mobility of approximately 300 cm^2·V·s^-1, and a resistivity of approximately 10^2 Ω·cm. A simple and effective method was proposed for chemical surface texturization of ZnTe using an HF：H2O2：H2O etchant. Textures with the sizes of approximately 1μm were produced on {100}, {110}, and { 111}zn surfaces after etching. The etchant is also very promising in crystal characterization because of its strong anisotropic character and Te-phase selectivity.展开更多
Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, includin...Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.展开更多
This paper demonstrates experimentally and numerically that a significant modification of spontaneous emission rate can be achieved near the surface of a three-dimensional photonic crystal. In experiments, semiconduct...This paper demonstrates experimentally and numerically that a significant modification of spontaneous emission rate can be achieved near the surface of a three-dimensional photonic crystal. In experiments, semiconductor coreshell quantum dots are intentionally confined in a thin polymer film on which a three-dimensional colloidal photonic crystal is fabricated. The spontaneous emission rate of quantum dots is characterised by conventional and time-resolved photoluminescence （PL） measurements. The modification of the spontaneous emission rate, which is reflected in the change of spectral shape and PL lifetime, is clearly observed. While an obvious increase in the PL lifetime is found at most wavelengths in the band gap, a significant reduction in the PL lifetime by one order of magnitude is observed at the short-wavelength band edge. Numerical simulation reveals a periodic modulation of spontaneous emission rate with decreasing modulation strength when an emitter is moved away from the surface of the photonic crystal. It is supported by the fact that the modification of spontaneous emission rate is not pronounced for quantum dots distributed in a thick polymer film where both enhancement and suppression are present simultaneously. This finding provides a simple and effective way for improving the performance of light emitting devices.展开更多
A new copper（1）-lead（Ⅱ） oxyhalide, CuPb2（OH）2Cl3, has been prepared by hydrothermal reaction and structurally characterized by single-crystal X-ray analysis. The compound crystallizes in tetragonal, space group...A new copper（1）-lead（Ⅱ） oxyhalide, CuPb2（OH）2Cl3, has been prepared by hydrothermal reaction and structurally characterized by single-crystal X-ray analysis. The compound crystallizes in tetragonal, space group 14（1）/acd with a = b = 13.77（1）, c = 15.38（1） A, V = 2916.2（2）, Z = 4, Mr = 618.29, Dc = 5.633 g/cm^3,μ = 49.97（2） mm^-1, F（000） = 4192, the final R = 0.0204 and wR = 0.0452 for 757 observed reflections with I 〉 2σ（I）. The structure of CuPb2（OH）2Cl3 contains one-dimensional helical chains built by CuCl4 tetrahedra with comer-sharing along the c-axis, in which the Pb^2＋ and OH^- ions are located at the voids between chains. Optical reflectance spectrum measurements indicate that it is a semiconductor with a band-gap of 3.23 eV.展开更多
文摘Considering two beams propagate in semiconductor crystal, this paper discusses the polarization dependence of pump beam-induced intensity attenuation of probe beam due to two-photon absorption （TPA）. Numerical calculation and experimental measurement demonstrate that TPA coefficient is polarization dependent. For homogeneous materials, probe beam attenuation arises from the imaginary part of diagonal and off-diagonal components of third-order nonlinear susceptibilities.
基金supported by the National Natural Science Foundation of China(Grant Nos.51672180,51622306,and 21673151)Collaborative Innovation Center of Suzhou Nano Science&Technology+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and Devices
文摘Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are promising candidates for realizing high-performance photodetectors. Here, after a brief resume of photodetector performance parameters and operation mechanisms, we review the recent advancements in application of SMOSCs as photodetectors, including photoconductors, phototransistors, and photodiodes. More importantly, the SMOSC-based photodetectors are further categorized according to their detection regions that cover a wide range from ultraviolet to near infrared. Finally, challenges and outlooks of SMOSC-based photodetectors are provided.
基金This work was supported by the National Natural Science Foundation of China(Nos.51973147,61904117,51821002 and 51672180)the Natural Science Foundation of Jiangsu Province of China(No.BK20180845)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the 111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and DevicesThe authors thank the Collaborative Innovation Center of Suzhou Nano Science and Technology(Nano-CIC),Soochow University and Beamline BLI4B1(Shanghai Synchrotron Radiation Facility)for providing beam time.
文摘Owing to enhanced charge transport efficiency arising from the ultrathin nature,two-dimensional(2D)organic semiconductor single crystals(OSSCs)are emerging as a fascinating platform for high-performance organic field-effect transistors(OFETs).However,ucoffee-ring"effect induced by an evaporation-induced convective flow near the contact line hinders the large-area growth of 2D OSSCs through a solution process.Here,we develop a new strategy of suppressing the"coffee-ring"effect by using an organic semiconductor:polymer blend solution.With the high-viscosity polymer in the organic solution,the evaporation-induced flow is remarkably weakened,ensuring the uniform molecule spreading for the 2D growth of the OSSCs.As an example,wafer-scale growth of crystalline film consisting of few-layered 2,7-didecylbenzothienobenzothiophene(C10-BTBT)crystals was successfully accomplished via blade coating.OFETs based on the crystalline film exhibited a maximum hole mobility up to 12.6 cm^2·V^-1·s^-1,along with an average hole mobility as high as 8.2 cm^2·V^-1·s^-1.Our work provides a promising strategy for the large-area growth of 2D OSSCs toward high-performance organic electronics.
基金partially supported by National Natural Science Foundation of China(Grant Nos.11174147,11175152 and11704326)the Funding of Jiangsu Innovation Program for Graduate Education(Grant No.KYLX15_0316)the Fundamental Research Funds for the Central Universities
文摘The tunable terahertz（THz） filter has been designed and studied, which is composed of 1D photonic crystal（PC） containing a defect layer of semiconductor Ga As. The analytical solution of 1D defective PC（1DDPC） is deduced based on the transfer matrix method, and the electromagnetic plane wave numerical simulation of this 1DDPC is performed by using the finite element method. The calculated and simulated results have confirmed that the filtering transmittance of this 1DDPC in symmetric structure of air/（Si/SiO_2）~N/GaAs/（SiO_2/Si）~N/air is far higher than in asymmetric structure of air/（Si/SiO_2）~N/GaAs/（Si/SiO_2）~N/air, where the filtering frequency can be tuned by the external pressure. It can provide a feasible route to design the external pressure-controlled THz filter based on 1DPC with a defective semiconductor.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFB0401804,2016YFB0402203,2016YFA0301102,and 2017YFA0206400)the National Natural Science Foundation of China(Grant Nos.91850206,61535013,61137003,61321063,and 61404133)the Special Fund for Strategic Pilot Technology,Chinese Academy of Sciences(Grant Nos.XDB24010100,XDB24010200,XDB24020100,and XDB24030100)
文摘By combing artificial micro–nano structures, photonic crystals（PCs）, with traditional semiconductor laser material to realize the dynamic collaborative control of photonic states and confined electrons, the band engineering of the PC has been confirmed. This brings new development space for the semiconductor laser, such as for low threshold and high efficiency.Based on a series of works by Zheng＇s group, this paper has reviewed kinds of PC lasers including electrical injection PC vertical cavity and lateral cavity surface-emitting lasers, and PC high beam quality lasers, to show that the PC is vital for promoting the continuous improvement of semiconductor laser performance at present and in the future.
基金Supported by the Ministry of Education and Science of the Russian Federation under Grant No 2271
文摘We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement of probes. The final expressions for identifying the electrical conductivity are presented in the form of a series of analytic functions. The suggested method is experimentally verified, and practical recommendations of how to apply it are also provided.
文摘Photonic crystals(PCs) have attracted much considerable research attention in the past two decades. They are artificially fabricated periodic dielectric structures. The periodic dielectric structures have photonic band gap(PBG) and are referred to as photonic band gap materials. This paper mainly introduces one-dimensional (1-D) and 2D PCs applied in the semiconductor lasers.
基金financially supported by the National Basic Research Program of China (No. 2011CB610406)the National Natural Science Foundation of China (No. 51372205)+3 种基金supported by the 111 Project of China (No. B08040)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20116102120014)the Northwestern Polytechnical University Foundation for Fundamental Researchthe Research Fund of the State Key Laboratory of Solidification Processing (NWPU)
文摘Using tellurium as a solvent, we grew ZnTe ingots of 30 mm in diameter and 70 mm in length by a temperature gradient solution growth method. Hall tests conducted at 300 K indicated that the as-grown ZnTe exhibits p-type conductivity, with a carrier concentration of approximately 10^14cm^-3, a mobility of approximately 300 cm^2·V·s^-1, and a resistivity of approximately 10^2 Ω·cm. A simple and effective method was proposed for chemical surface texturization of ZnTe using an HF：H2O2：H2O etchant. Textures with the sizes of approximately 1μm were produced on {100}, {110}, and { 111}zn surfaces after etching. The etchant is also very promising in crystal characterization because of its strong anisotropic character and Te-phase selectivity.
文摘Functional crystals are the basic materials for the development of modern science and technology and are playing key roles in the modern information era. In this paper, we review functional crystals in China, including research history, significant achievements, and important applications by highlighting the most recent progress in research. Challenges for the development of functional materials are discussed and possible directions for development are proposed by focusing on potential strengths of these materials.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974060 and 10774050)the Program for Innovative Research Team of the Higher Education in Guangdong,China (Grant No. 06CXTD005)
文摘This paper demonstrates experimentally and numerically that a significant modification of spontaneous emission rate can be achieved near the surface of a three-dimensional photonic crystal. In experiments, semiconductor coreshell quantum dots are intentionally confined in a thin polymer film on which a three-dimensional colloidal photonic crystal is fabricated. The spontaneous emission rate of quantum dots is characterised by conventional and time-resolved photoluminescence （PL） measurements. The modification of the spontaneous emission rate, which is reflected in the change of spectral shape and PL lifetime, is clearly observed. While an obvious increase in the PL lifetime is found at most wavelengths in the band gap, a significant reduction in the PL lifetime by one order of magnitude is observed at the short-wavelength band edge. Numerical simulation reveals a periodic modulation of spontaneous emission rate with decreasing modulation strength when an emitter is moved away from the surface of the photonic crystal. It is supported by the fact that the modification of spontaneous emission rate is not pronounced for quantum dots distributed in a thick polymer film where both enhancement and suppression are present simultaneously. This finding provides a simple and effective way for improving the performance of light emitting devices.
基金financially supported by the National Basic Research Program of China(No.2012CB921701)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe Scientific Research Foundation of Education Bureau of Hubei Province(No.D20101504)
文摘A new copper（1）-lead（Ⅱ） oxyhalide, CuPb2（OH）2Cl3, has been prepared by hydrothermal reaction and structurally characterized by single-crystal X-ray analysis. The compound crystallizes in tetragonal, space group 14（1）/acd with a = b = 13.77（1）, c = 15.38（1） A, V = 2916.2（2）, Z = 4, Mr = 618.29, Dc = 5.633 g/cm^3,μ = 49.97（2） mm^-1, F（000） = 4192, the final R = 0.0204 and wR = 0.0452 for 757 observed reflections with I 〉 2σ（I）. The structure of CuPb2（OH）2Cl3 contains one-dimensional helical chains built by CuCl4 tetrahedra with comer-sharing along the c-axis, in which the Pb^2＋ and OH^- ions are located at the voids between chains. Optical reflectance spectrum measurements indicate that it is a semiconductor with a band-gap of 3.23 eV.
