学科建设

学术报告:Facet-induced optical and magnetic behavior in semiconductor micro/nanostructures

报告题目:Facet-induced optical and magnetic behavior in semiconductor micro/nanostructures

报告人:吴兴龙教授(杰青、长江、南京大学)

报告时间:110日(星期二)下午1400

报告地点:物理科技楼101

报告摘要:Semiconducting micro/nanostructures have many novel physical and chemical characters and are the basis for multi-discipline crossing investigations. Since many atoms are local at the surface of micro/nano-structured materials, effective control of surface structure can help to seek new physical and chemical properties and further find valuable applications. In this report, I will introduce surface structural control of polar semiconducting micro/nano-materials and their optical and electronic properties. 1) Introduce the growth of cubic In2O3 microparticles with exposed {001} facets as well as single morphology and size [1,2]. The morphological evolution mechanism enables precise facet cutting possible. The synthesized cubic In2O3 microparticles possess superior photoelectrocatalytic activity and excellent chemical and structural stability in oxygen evolution reaction [2,3]. The technique and concept of “facet cutting” can be extended to other facet-specic materials in applications such as sensors, solar cells, and lithium batteries. 2) Introduce the formation of crystalline b-FeSi2 nanocubes with two {100} facets and four {011} lateral facets. Such b-FeSi2 nanocubes exhibit strong room-temperature ferromagnetism with saturation magnetization of 15 emu/g. The ferromagnetism is tentatively explained with a simplified model including both the itinerant electrons in surface states and the local moments on Fe atoms near the surfaces. The room-temperature ferromagnetism can be manipulated under light irradiation [4]. The semiconducting b-FeSi2 nanocubes may have large potential in silicon-based spintronic applications. 3) Introduce the formation mechanism of core/shell structured ZnO microspheres with uniform-sizes. Low-frequency Raman scattering investigation indicates that such a core/shell ZnO mesocrystal can produce a radiative emission at 0.36 THz due to mechanical resonance under excitation with a continuous green-wavelength laser. 0.016% of the incident power is converted into terahertz radiation, which corresponds to a quantum efficiency of 33%, making the ZnO microspheres competitive with existing terahertz-emitting materials [5,6].


References

1.M. Meng, X. L. Wu, X. B. Zhu, L. Yang, Z. X. Gan, X. S. Zhu, L. Z, Liu, and Paul K. Chu, Cubic In2O3 Microparticles for Effcient Photoelectrochemical Oxygen Evolution, J. Phys. Chem. Lett. 5, 4298 (2014).

2.M. Meng, X. L. Wu, X. B. Zhu, X. S. Zhu, and Paul K. Chu, Facet Cutting and Hydrogenation of In2O3 Nanowires for Enhanced Photoelectrochemical Water Splitting, ACS Appl. Mater. Interface 6, 4081 (2014).

3.M. Sun, S. J. Xiong, X. L. Wu, C. Y. He, T. H. Li, and Paul K. Chu, Enhanced Photocatalytic Oxygen Evolution by Crystal Cutting, Adv. Mater. 25, 2035 (2013).

4.Z. Q. He, S. J. Xiong, S. Y. Wu, X. B. Zhu, M. Meng, and X. L. Wu, Strong Facet-Induced and Light-Controlled Room-Temperature Ferromagnetism in Semiconducting β-FeSi2 Nanocubes, J. Am. Chem. Soc. 137, 11419 (2015).

5.Z. Liu, X. D. Wen, X. L. Wu, Y. J. Gao, H. T. Chen, J. Zhu, and Paul K. Chu, Instrinc Dipole-Field-Driven Mesoscale Crystallization of Core-Shell ZnO Mesocrystal Microspheres, J. Am. Chem. Soc. 131, 9405 (2009).

6.X. L. Wu, S. J. Xiong, Z. Liu, J. Chen, J. C. Shen, T. H. Li, P. H. Wu, and Paul K. Chu, Green Light Stimulates Terahertz Emission from Mesocrystal Microspheres, Nat. Nanotechnol. 6,103 (2011)


报告人简介:吴兴龙,1964年生,19952月博士毕业于南京大学物理系凝聚态物理专业,随后留校工作。现为南京大学物理学院教授、博士生导师,物理学院副院长。长期从事纳米半导体发光材料的微结构、声子特性和发光机理的研究,在包括Nature NanotechnolPRLJACSNano LettAMAngew ChemACS Nano等杂志上发表论文300余篇,论文被同行在国际杂志上他引七仟余次,单篇他人引用最高900余次。2002年获国家杰出青年基金资助,2007年入选教育部长江学者特聘教授。近年来主持和参与国家科技部 “973”项目(课题项目负责人)、国家自然科学基金委、教育部、江苏省自然科学基金委等重点和面上项目多项。曾获国家自然科学四等奖、江苏省科技进步一、二等奖各一次。



Copyright2012 苏州大学 物理科学与技术学院 能源学院 版权所有  Powered By SiteServer CMS