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物理学院“博约学术沙龙”系列报告(总第144期)

发布日期:2017年11月20日
时  间:   2017年11月20日(星期一)下午 14:30
地  点:   中心教学楼610
报告一:硕士生报告    时间: 14:30-15:00
题  目:基于纳米压印法制备二氧化硅微纳结构基片及其光学特性研究
报告人:梁倞                  指导老师:刘瑞斌 

摘要:
本文利用溶胶凝胶法制备具有高保真度的紫外固化SiO2压印胶,并通过无机改性手段提高其透明度,最终固化产物已被确认主要为非晶态SiO2。随后的实验证明本论文中的压印胶可以通过基底完整压抑光刻法制备出结构规整、保真度高、性质稳定、光学特性优秀的SiO2周期性微纳结构。矩形SiO2周期结构对450~1000 nm波长光的折射率n从1.44变化到1.42。通过研究其反射衍射行为,确定矩形SiO2周期结构具有优越的色散特性。实验和数值模拟皆表明矩形SiO2周期结构具有随入射角的改变的偏振调制特性,并且首次探讨了衬底均匀度对各阶次衍射点的强度的影响。SiO2微纳圆柱阵列对波长处在~500 nm的光波有较强的吸收。研究SiO2微纳圆柱阵列的反射衍射和透射衍射行为,特别对其偏振特性进行量化分析,确定这种微纳结构具有良好的色度色散和透射衍射效应,且对偏振光没有明显的选择特性。
报告二:硕士生报告    时间:15:00-15:30
题  目:GaSe压电光电子学的研究Robust Piezophototronic Effect in GaSe Nanosheets
报告人:贾探花                 指导老师:吴汉春

摘要:
Piezo-phototronic devices, where optoelectrical properties are directly influenced by mechanical stimuli, are highly desirable for applications in wearable devices and human-machine interfaces. Here, we investigate the piezo-phototronic properties of GaSe nanosheets. It is found that GaSe shows a robust piezo-phototronic response. The photoconductivity, conductivity, and photoluminescence (PL) of GaSe nanosheets can be enhanced linearly and regulated simultaneously via mechanical strain at room temperature. Finally, its suitablity for flexible optoelectronic-mechanical applications is demonstrated by repeatedly bending GaSe devices. The manual bending of GaSe reliably enhances the current by more than a factor of 240. The robust piezo-phototronic response combined with excellent stretchability suggest that GaSe is a valuable material for flexible optoelectronic-mechanical applications.

报告三:硕士生报告    时间:15:30-16:00
题  目: The aggregation of Fe3+ and their d-d radiative transitions in ZnSe:Fe3+ nanobelts by CVD growth
报告人:梁变变                 指导老师: 石丽洁

摘要:
Transition metal (TM) doped ll-Vl semiconductors attracted a lot of attentions due to their luminescence and diluted magnetism. In this paper, Fe3+-doped ZnSe nanobelts (NBs) were grown by facile CVD method. The morphology detected by SEM is smooth and clean, and the element composition measured by EDS confirms that the Fe3+ ions have been incorporated into ZnSe NBs successfully. The micro-Raman scattering spectra demonstrate that as-prepared NBs are zinc blend structure. And the Raman spectra of Fe3+-doped NBs were compared with those of pure and Fe2+-doped reference samples. The former with higher signal to noise ratio, the enhanced 2LO mode, stronger LO mode redshift and larger intensity ratio of LO/TO mode, as well as the lower acoustic phonon modes, confirms the better crystallization and the stronger electron-phonon coupling with Fe3+ incorporation. The emission of single Fe3+ ion, assigned to the 4T1 →6A1 transition, was observed at about 570nm. And increasing Fe3+ ions doping concentration caused the formation of different Fe-Fe coupled pairs in the lattice, which emit light at about 530-555nm for antiferromagnetic coupled pair possible staying with the stacking faults, and at about 620-670nm for ferromagnetic coupled pair.

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