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Polarity continuation and frustration in ZnSe nanospirals.

Li L, Tu F, Jin L, Choy WC, Gao Y, Wang J - Sci Rep (2014)

Bottom Line: ZnSe nanospirals including structures with polarity continuation and polarity frustration are simultaneously observed at atomic resolution.Through careful analysis of polarity within each dumbbell based on aberration-corrected high-angle annular-dark-field imaging, polarity continuation across parallel polytype interfaces as well as the surrounding Z-shape faulted dipoles is verified.Moreover, polarity frustration across regions with different stacking sequence, which would lead to accumulations of boundary interface charges in the triangular-shaped mixed regions with potential optoelectronic applications, is carefully studied.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanoscale Characterization and Devices, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.

ABSTRACT
ZnSe nanospirals including structures with polarity continuation and polarity frustration are simultaneously observed at atomic resolution. Through careful analysis of polarity within each dumbbell based on aberration-corrected high-angle annular-dark-field imaging, polarity continuation across parallel polytype interfaces as well as the surrounding Z-shape faulted dipoles is verified. Moreover, polarity frustration across regions with different stacking sequence, which would lead to accumulations of boundary interface charges in the triangular-shaped mixed regions with potential optoelectronic applications, is carefully studied.

No MeSH data available.


Related in: MedlinePlus

Overall features of ZnSe nanospirals.(a) SEM image of ZnSe nanospirals. (b) HAADF image of a broken piece of ZnSe nanospirals with much rougher inner side surfaces. (c) TEM image of part of a selected nanospiral with parallel dark lines along the growth direction. Two featured regions are framed by red and blue circles, and the HRTEM images with similar features are presented in (d) and (e), respectively. The locations of Lomer-Cottrell partial dislocations in (d) are indicated by red arrows, and the mixed regions of different stacking sequence in (e) are labeled by blue arrows.
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f1: Overall features of ZnSe nanospirals.(a) SEM image of ZnSe nanospirals. (b) HAADF image of a broken piece of ZnSe nanospirals with much rougher inner side surfaces. (c) TEM image of part of a selected nanospiral with parallel dark lines along the growth direction. Two featured regions are framed by red and blue circles, and the HRTEM images with similar features are presented in (d) and (e), respectively. The locations of Lomer-Cottrell partial dislocations in (d) are indicated by red arrows, and the mixed regions of different stacking sequence in (e) are labeled by blue arrows.

Mentions: The ZnSe nanospirals are bent into spiral-like shapes with relatively rougher inner side surfaces, as represented by the SEM image in Figure 1a and HAADF image in Figure 1b. The nanospirals are easily broken into small pieces with belt-like shape during TEM sample preparation due to their large sizes. The growth direction is along <−211> axis, and the [111] axes are always pointing towards the center of the nanospiral. There is a high density of stacking faults on {111} planes featured by the parallel dark lines along the growth direction in Figure 1c. Two typical regions are framed by red and blue circles, and the high resolution transmission electron microscopy (HRTEM) images with similar features are presented in Figures 1d–e, respectively. Figure 1d shows several stacking faults on the {111} planes intersecting stacking faults on the {−111} planes, forming the so-called Z-shape faulted dipoles. Lomer-Cottrell partial dislocations would form at the intersection points, as indicated by the red arrows, which are reported to be responsible for the spiral-like morphology of the ZnSe nanospirals17. Figure 1e also shows many stacking faults on the {111} planes. The blue arrows indicate mixed regions where the two sides have different stacking sequence. The detailed structural information at those regions are not obtainable due to the limited resolution of the microscope used for HRTEM imaging, and the unavoidable image delocalization effect that occurs in a microscope without aberration correction for the imaging mode.


Polarity continuation and frustration in ZnSe nanospirals.

Li L, Tu F, Jin L, Choy WC, Gao Y, Wang J - Sci Rep (2014)

Overall features of ZnSe nanospirals.(a) SEM image of ZnSe nanospirals. (b) HAADF image of a broken piece of ZnSe nanospirals with much rougher inner side surfaces. (c) TEM image of part of a selected nanospiral with parallel dark lines along the growth direction. Two featured regions are framed by red and blue circles, and the HRTEM images with similar features are presented in (d) and (e), respectively. The locations of Lomer-Cottrell partial dislocations in (d) are indicated by red arrows, and the mixed regions of different stacking sequence in (e) are labeled by blue arrows.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4265773&req=5

f1: Overall features of ZnSe nanospirals.(a) SEM image of ZnSe nanospirals. (b) HAADF image of a broken piece of ZnSe nanospirals with much rougher inner side surfaces. (c) TEM image of part of a selected nanospiral with parallel dark lines along the growth direction. Two featured regions are framed by red and blue circles, and the HRTEM images with similar features are presented in (d) and (e), respectively. The locations of Lomer-Cottrell partial dislocations in (d) are indicated by red arrows, and the mixed regions of different stacking sequence in (e) are labeled by blue arrows.
Mentions: The ZnSe nanospirals are bent into spiral-like shapes with relatively rougher inner side surfaces, as represented by the SEM image in Figure 1a and HAADF image in Figure 1b. The nanospirals are easily broken into small pieces with belt-like shape during TEM sample preparation due to their large sizes. The growth direction is along <−211> axis, and the [111] axes are always pointing towards the center of the nanospiral. There is a high density of stacking faults on {111} planes featured by the parallel dark lines along the growth direction in Figure 1c. Two typical regions are framed by red and blue circles, and the high resolution transmission electron microscopy (HRTEM) images with similar features are presented in Figures 1d–e, respectively. Figure 1d shows several stacking faults on the {111} planes intersecting stacking faults on the {−111} planes, forming the so-called Z-shape faulted dipoles. Lomer-Cottrell partial dislocations would form at the intersection points, as indicated by the red arrows, which are reported to be responsible for the spiral-like morphology of the ZnSe nanospirals17. Figure 1e also shows many stacking faults on the {111} planes. The blue arrows indicate mixed regions where the two sides have different stacking sequence. The detailed structural information at those regions are not obtainable due to the limited resolution of the microscope used for HRTEM imaging, and the unavoidable image delocalization effect that occurs in a microscope without aberration correction for the imaging mode.

Bottom Line: ZnSe nanospirals including structures with polarity continuation and polarity frustration are simultaneously observed at atomic resolution.Through careful analysis of polarity within each dumbbell based on aberration-corrected high-angle annular-dark-field imaging, polarity continuation across parallel polytype interfaces as well as the surrounding Z-shape faulted dipoles is verified.Moreover, polarity frustration across regions with different stacking sequence, which would lead to accumulations of boundary interface charges in the triangular-shaped mixed regions with potential optoelectronic applications, is carefully studied.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanoscale Characterization and Devices, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.

ABSTRACT
ZnSe nanospirals including structures with polarity continuation and polarity frustration are simultaneously observed at atomic resolution. Through careful analysis of polarity within each dumbbell based on aberration-corrected high-angle annular-dark-field imaging, polarity continuation across parallel polytype interfaces as well as the surrounding Z-shape faulted dipoles is verified. Moreover, polarity frustration across regions with different stacking sequence, which would lead to accumulations of boundary interface charges in the triangular-shaped mixed regions with potential optoelectronic applications, is carefully studied.

No MeSH data available.


Related in: MedlinePlus