Carbon nanotubes(CNTs)hold immense promise for a wide array of applications due to their exceptional physical and chemical properties.Understanding and controlling their structural characteristics,particu-larly the di...Carbon nanotubes(CNTs)hold immense promise for a wide array of applications due to their exceptional physical and chemical properties.Understanding and controlling their structural characteristics,particu-larly the diameter and number of walls,is crucial for harnessing their full potential.We investigated the relationship between these parameters for both commercially available and lab-scale CNTs,spanning a wide range of outer diameters(1-13 nm)and numbers of walls(1-13).Our findings revealed a com-monality among the structural diversity,rather than a random distribution,as evidenced by a piecewise linear relationship between the outer diameter and number of walls,with an inflection point occurring at approximately 4 nm in diameter.This observation is unexpected,as the CNTs were synthesized using different approaches and growth conditions;yet,as a group,they exhibit a“structural scaling”.Addi-tionally,we made an intriguing observation:despite increases in outer diameter and number of walls,the inner diameters remained relatively constant(4-5 nm)for thicker CNTs with more than three walls.These results suggest that structural properties can be estimated based on diameter,which not only ad-vances our fundamental understanding of CNT synthesis but also provides practical insights for tailoring CNT properties for various applications.展开更多
The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relax...The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relaxed SiGe buffer layer provided preferential nucleation sites for quantum dots. Burgers vector analysis using plan-view transmission electron microscopy (TEM) verified that the preferential nucleation sites of Ge SAQDs depended on the Burgers vector direction of corresponding dislocations. The measurement of the lateral distance between SAQDs and dislocations together with crosssection TEM observation clarified that the location of SAQDs was at the intersection of the dislocation slip plane and the top surface. The misfit strain should be an additional factor governing the uniformity in size, shape and distribution of Ge SAQDs.展开更多
文摘Carbon nanotubes(CNTs)hold immense promise for a wide array of applications due to their exceptional physical and chemical properties.Understanding and controlling their structural characteristics,particu-larly the diameter and number of walls,is crucial for harnessing their full potential.We investigated the relationship between these parameters for both commercially available and lab-scale CNTs,spanning a wide range of outer diameters(1-13 nm)and numbers of walls(1-13).Our findings revealed a com-monality among the structural diversity,rather than a random distribution,as evidenced by a piecewise linear relationship between the outer diameter and number of walls,with an inflection point occurring at approximately 4 nm in diameter.This observation is unexpected,as the CNTs were synthesized using different approaches and growth conditions;yet,as a group,they exhibit a“structural scaling”.Addi-tionally,we made an intriguing observation:despite increases in outer diameter and number of walls,the inner diameters remained relatively constant(4-5 nm)for thicker CNTs with more than three walls.These results suggest that structural properties can be estimated based on diameter,which not only ad-vances our fundamental understanding of CNT synthesis but also provides practical insights for tailoring CNT properties for various applications.
文摘The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relaxed SiGe buffer layer provided preferential nucleation sites for quantum dots. Burgers vector analysis using plan-view transmission electron microscopy (TEM) verified that the preferential nucleation sites of Ge SAQDs depended on the Burgers vector direction of corresponding dislocations. The measurement of the lateral distance between SAQDs and dislocations together with crosssection TEM observation clarified that the location of SAQDs was at the intersection of the dislocation slip plane and the top surface. The misfit strain should be an additional factor governing the uniformity in size, shape and distribution of Ge SAQDs.
