This paper studies the equilibrium geometries and electronic properties of Be n and Be n Li clusters, up to n=15, by using density-functional theory(DFT) at B3LYP/6-31G(d) level. The lowest-energy structures of Be n a...This paper studies the equilibrium geometries and electronic properties of Be n and Be n Li clusters, up to n=15, by using density-functional theory(DFT) at B3LYP/6-31G(d) level. The lowest-energy structures of Be n and Be n Li clusters were determined. The results indicate that a single lithium impurity enhances the stability and chemical reactivity of the beryllium clusters. It finds that the geometries of the host clusters change significantly after the addition of the lithium atom for n ≥8. The lithium impurity prefers to be on the periphery of beryllium clusters, and occupies vertex sites. Both Be 4 Li, Be 9 Li, and Be 13 Li were found to be particularly stable with higher average binding energy, local peaks of second-order energy difference and fragmentation energies. For all the Be n Li clusters studied, we found charge transfers from the Li to Be site and co-existence of covalent and metallic bonding characteristics.展开更多
Pb(Zr0.53, Ti0.47)O3 (PZT) films were directly deposited on Si substrates without a buffer layer by pulsed laser deposition. Only(110)-oriented PZT peaks (other than Si substrate peaks) were observed from the XRD data...Pb(Zr0.53, Ti0.47)O3 (PZT) films were directly deposited on Si substrates without a buffer layer by pulsed laser deposition. Only(110)-oriented PZT peaks (other than Si substrate peaks) were observed from the XRD data. The electrical properties of the PZT/Si capacitor were characterized in terms of both the capacitance versus voltage (C-V) and current versus voltage (I-V) measurements. The clockwise trace of the C-V curve shows ferroelectric polarization switching, as is expected. From the I-V curves, the Schottky emission and spacecharge-limited-current behaviour are found to be the mainly leakage current mechanism in a certain electric field range in the negative and positive bias, respectively.展开更多
基金Project supported by the Xinjiang Normal University Excellent Young Teachers’ Foundation, China (Grant No XJNU0730)Xinjiang Normal University Priority Developing Disciplines’ Foundation
文摘This paper studies the equilibrium geometries and electronic properties of Be n and Be n Li clusters, up to n=15, by using density-functional theory(DFT) at B3LYP/6-31G(d) level. The lowest-energy structures of Be n and Be n Li clusters were determined. The results indicate that a single lithium impurity enhances the stability and chemical reactivity of the beryllium clusters. It finds that the geometries of the host clusters change significantly after the addition of the lithium atom for n ≥8. The lithium impurity prefers to be on the periphery of beryllium clusters, and occupies vertex sites. Both Be 4 Li, Be 9 Li, and Be 13 Li were found to be particularly stable with higher average binding energy, local peaks of second-order energy difference and fragmentation energies. For all the Be n Li clusters studied, we found charge transfers from the Li to Be site and co-existence of covalent and metallic bonding characteristics.
文摘Pb(Zr0.53, Ti0.47)O3 (PZT) films were directly deposited on Si substrates without a buffer layer by pulsed laser deposition. Only(110)-oriented PZT peaks (other than Si substrate peaks) were observed from the XRD data. The electrical properties of the PZT/Si capacitor were characterized in terms of both the capacitance versus voltage (C-V) and current versus voltage (I-V) measurements. The clockwise trace of the C-V curve shows ferroelectric polarization switching, as is expected. From the I-V curves, the Schottky emission and spacecharge-limited-current behaviour are found to be the mainly leakage current mechanism in a certain electric field range in the negative and positive bias, respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60676032, 60577030, and 60476028, and the National Key Basic Research Special Foundation of China under Grant No TG 2007CB307004.
文摘电的特征在 <SUB>0.05</SUB > Ga <SUB>0.95</SUB > N/Al <SUB>0.07</SUB > Ga <SUB>0.93</SUB > N 并且在 <SUB>0.05</SUB > Ga <SUB>0.95</SUB > N/GaN 多重量井(MQW ) 紫外轻射出的二极管(紫外带) 在 400 nm，波长被测量。为 InGaN/AlGaN MQW LEDs，想象力因素和平行电阻类似于 InGaN/GaN MQW LEDs 的那些，这被发现，当系列电阻是 two times 时更大。这被建议艾尔 <SUB>0.07</SUB > Ga <SUB>0.93</SUB > N 障碍层没改变水晶质量和 p-n 连接任何一个的电的特征，但是带更大的系列电阻。作为结果， InGaN/AlGaN MQW LEDs 尽管他们显示出更高轻的产量效率，承受更多的严肃的热驱散问题。
