从光电转换的基本原理出发,分析了禁带宽度 Eg、薄膜以及异质结对材料的选择原则。在异质结理论的基础上,分析了 p-ZnTe/n-CdTe 异质结的结区结构,在两种材料的界面处,导带底形成了不连续的“断口”,价带顶 p 区一侧形成尖峰,n 区一侧...从光电转换的基本原理出发,分析了禁带宽度 Eg、薄膜以及异质结对材料的选择原则。在异质结理论的基础上,分析了 p-ZnTe/n-CdTe 异质结的结区结构,在两种材料的界面处,导带底形成了不连续的“断口”,价带顶 p 区一侧形成尖峰,n 区一侧形成凹口。当热平衡时,由于导带中电子从 n 区到 p 区所遇到的势垒大于价带中空穴从 p 区到 n 区的势垒,所以,通过势垒的主要是空穴流。讨论了 p-Zn-Te/n-CdTe 异质结的制作方法及工艺问题。最后,给出了测试结果。展开更多
Polycrystalline La-doped BaTiO_(3)(Ba_(1-x)La_(x)TiO_(3))[x¼0;0:0005;0:001;0:003]ceramics(denoted as BTO,BLT1,BLT2,BLT3)were synthesized by conventional solid-state reaction method and characterized by X-ray diff...Polycrystalline La-doped BaTiO_(3)(Ba_(1-x)La_(x)TiO_(3))[x¼0;0:0005;0:001;0:003]ceramics(denoted as BTO,BLT1,BLT2,BLT3)were synthesized by conventional solid-state reaction method and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Raman spectroscopy.XRD and Raman spectra revealed single-phase tetragonal perovskite crystalline structure.Well-saturated polarization–electric field(P–E)hysteresis loops were observed with the measurement frequency of 50Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350J/cm^(3) with energy efficiency(n)-9%,which is useful in energy storage capacitor applications.Dielectric studies revealed anomalies around 415–420K and near the Curie temperature.The latter is attributed to the ferroelectric to paraelectric phase transition.Better dielectric performances were obtained for La-doped samples sintered at 1350℃ for 4h.Grain growth is inhibited with lanthanum(La)incorporation into the BTO lattice.Room temperature semiconducting behavior with positive temperature coefficient of resistivity(PTCR)behavior at TC is attributed to electron compensation mechanism.展开更多
文摘从光电转换的基本原理出发,分析了禁带宽度 Eg、薄膜以及异质结对材料的选择原则。在异质结理论的基础上,分析了 p-ZnTe/n-CdTe 异质结的结区结构,在两种材料的界面处,导带底形成了不连续的“断口”,价带顶 p 区一侧形成尖峰,n 区一侧形成凹口。当热平衡时,由于导带中电子从 n 区到 p 区所遇到的势垒大于价带中空穴从 p 区到 n 区的势垒,所以,通过势垒的主要是空穴流。讨论了 p-Zn-Te/n-CdTe 异质结的制作方法及工艺问题。最后,给出了测试结果。
基金This work was supported by the National Science Foundation under grant NSF-EFRI RESTOR#1038272.
文摘Polycrystalline La-doped BaTiO_(3)(Ba_(1-x)La_(x)TiO_(3))[x¼0;0:0005;0:001;0:003]ceramics(denoted as BTO,BLT1,BLT2,BLT3)were synthesized by conventional solid-state reaction method and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Raman spectroscopy.XRD and Raman spectra revealed single-phase tetragonal perovskite crystalline structure.Well-saturated polarization–electric field(P–E)hysteresis loops were observed with the measurement frequency of 50Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350J/cm^(3) with energy efficiency(n)-9%,which is useful in energy storage capacitor applications.Dielectric studies revealed anomalies around 415–420K and near the Curie temperature.The latter is attributed to the ferroelectric to paraelectric phase transition.Better dielectric performances were obtained for La-doped samples sintered at 1350℃ for 4h.Grain growth is inhibited with lanthanum(La)incorporation into the BTO lattice.Room temperature semiconducting behavior with positive temperature coefficient of resistivity(PTCR)behavior at TC is attributed to electron compensation mechanism.
