金属铂(Ⅱ)-卟啉二聚体配合物的分子内π-π相互作用

合成了以不同链长的烷氧基柔性链相连接的金属铂(Ⅱ)-卟啉二聚体配合物并对其热稳定性,光谱性质及电化学性质做了研究。在浓度由10^-7 mol·dm^-3增大到10^-3 mol·dm^-3的过程中将配体与配合物的紫外-可见吸收光谱与光致发光光谱做了对比,发现配体与配合物的吸收光谱随浓度变化未出现改变,但发射光谱显现出随浓度增大而产生红移现象。当烷氧基柔性链中碳原子数大于4时,C6与C10配合物无论是高浓度下的溶液与升华固体薄膜中的荧光发射光谱均比配体有明显的红移,而短链的配合物无此性质。     

Investigations on mesa width design for 4H–SiC trench super junction Schottky diodes

Mesa width(WM) is a key design parameter for SiC super junction(SJ) Schottky diodes(SBD) fabricated by the trench-etching-and-sidewall-implant method. This paper carries out a comprehensive investigation on how the mesa width design determines the device electrical performances and how it affects the degree of performance degradation induced by process variations. It is found that structures designed with narrower mesa widths can tolerant substantially larger charge imbalance for a given BV target, but have poor specific on-resistances. On the contrary, structures with wider mesa widths have superior on-state performances but their breakdown voltages are more sensitive to p-type doping variation. Medium WMstructures(～ 2 μm) exhibit stronger robustness against the process variation resulting from SiC deep trench etching.Devices with 2-μm mesa width were fabricated and electrically characterized. The fabricated SiC SJ SBDs have achieved a breakdown voltage of 1350 V with a specific on-resistance as low as 0.98 m?·cm~2. The estimated specific drift onresistance by subtracting substrate resistance is well below the theoretical one-dimensional unipolar limit of SiC material.The robustness of the voltage blocking capability against trench dimension variations has also been experimentally verified for the proposed SiC SJ SBD devices.