2011
DOI: 10.1021/cg200828y
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Theoretical Analysis of Nucleation and Growth of ZnO Nanostructures in Vapor Phase Transport Growth

Abstract: This paper discusses the growth atmosphere, condensing species and nucleation conditions relevant to vapour phase transport growth of ZnO nanostructures, including the molecular parameters and thermodynamics of the gas phase ZnO molecule and its importance compared to atomic Zn and molecular O 2 . The partial pressure of molecular ZnO in a Zn/O 2 mix at normal ZnO growth temperatures is ∼ 6 × 10 −7 of the Zn partial pressures. In typical vapour phase transport growth conditions, using carbothermal reduction, t… Show more

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Cited by 13 publications
(18 citation statements)
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“…This is a reasonable estimate for the number of molecules arriving at the nanowires and is consistent with the fact that the calculated pressure and impingement rates are upper bounds based on thermodynamics. 19 The lengths calculated for two different growth times agree with the measured values, subject to the caveat above, showing good agreement for the predicted variation of nanowire lengths with time with the average measured lengths showing an increase in value with decreasing radius.…”
Section: Zno Nanowires Grown Via Vptsupporting
confidence: 68%
See 1 more Smart Citation
“…This is a reasonable estimate for the number of molecules arriving at the nanowires and is consistent with the fact that the calculated pressure and impingement rates are upper bounds based on thermodynamics. 19 The lengths calculated for two different growth times agree with the measured values, subject to the caveat above, showing good agreement for the predicted variation of nanowire lengths with time with the average measured lengths showing an increase in value with decreasing radius.…”
Section: Zno Nanowires Grown Via Vptsupporting
confidence: 68%
“…We have found previously 19 Figure 8: Nanowire length as a function of radius for sample grown for 40 minutes with a specific amount of O 2 and statistical analysis of data, as described in text Figure 9 shows the results for nanowires that were grown for 20 minutes in a specific amount of O 2 and with a similar statistical analysis to that shown for the data in Figure 7 and Figure 8, treating the radius as the independent variable in Figure 9(a) and the length as the independent variable in Figure 9 ZnO nanowires grown via VPT on an ordered arrays…”
Section: Zno Nanowires Grown Via Vptmentioning
confidence: 87%
“…Therefore, from the TEM analysis it is thought the surface chemical reaction of the etching process induces various forms of defects that act as accommodation sites. 36 Etching at defective areas on the surface of the Al 2 O 3 substrate is likely to be more effective than etching at areas with higher order which may lead to the heavy twinning that was observed within the nanoislands where a high concentration of surface defects was found (Figure 6c). It is worth recalling at this point that defects in the ZnO base layer identified in the early stages of growth near the Al 2 O 3 interface were not observed in the later stages of growth, which is most likely due to the temperature being higher once nanowire growth is initiated and the defects being annealed out.…”
Section: ■ Results and Discussionmentioning
confidence: 99%
“…36 An oriented crystalline ZnO growth develops from the nucleation points growing into a continuous film over the substrate, but we can expect the original sites of nucleation to be somewhat thicker than the rest of the film, and it is likely that these sites serve as points for nanowire growth to proceed. Once the conditions favor nanowire growth this is maintained until on completion, a continuous forest of dense but evenly spaced nanowires covers the entire etched region of the substrate.…”
Section: ■ Results and Discussionmentioning
confidence: 99%
“…By taking the data γ sv = 1.15 J/m 2 , s = 71.35 × 10 −30 m 3 , T = 823 K, and P /P 0 is of the order of 100 (Ref. 27), it follows that W c ZB ∼ 3 × 10 −9 m. This means that once the ZB slab is thicker than W c ZB , then the embryo of the blades will be accommodated and developed further. This value is comparable with our TEM observations, where the ZB slab is of the order of several nanometers.…”
Section: B Growth Mechanism Of the Hierarchical Structurementioning
confidence: 99%