Real-Time Observation of Morphological Transformations in II–VI Semiconducting Nanobelts via Environmental Transmission Electron Microscopy

Agarwal, Rahul; Zakharov, Dmitri N.; Krook, Nadia M.; Liu, Wenjing; Berger, Jacob S.; Stach, Eric A.; Agarwal, Ritesh

doi:10.1021/acs.nanolett.5b00520

Cited by 14 publications

(14 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of in situ transmission electron microscopy ( in situ TEM) in a controlled gas environment for the investigation of material evolution under reacting conditions is a real asset in several fields (Kodambaka et al ., ; Agarwal et al ., ), especially in the field of catalysis (Vendelbo et al ., ; Bremmer et al ., ). It allows studying the dynamical changes experienced by nanomaterials in terms of morphological, microstructural and chemical features, thus providing insight into their behaviour under various and controlled atmospheres.…”

Section: Introductionmentioning

confidence: 99%

Reactivity and structural evolution of urchin‐like Co nanostructures under controlled environments

Dembélé

Moldovan

Hirlimann

et al. 2017

Journal of Microscopy

View full text Add to dashboard Cite

In situ transmission electron microscopy (TEM) of samples in a controlled gas environment allows for the real time study of the dynamical changes in nanomaterials at high temperatures and pressures up to the ambient pressure (10 Pa) with a spatial resolution close to the atomic scale. In the field of catalysis, the implementation and quantitative use of in situ procedures are fundamental for a better understanding of the behaviour of catalysts in their environments and operating conditions. By using a microelectromechanical systems (MEMS)-based atmospheric gas cell, we have studied the thermal stability and the reactivity of crystalline cobalt nanostructures with initial 'urchin-like' morphologies sustained by native surface ligands that result from their synthesis reaction. We have evidenced various behaviors of the Co nanostructures that depend on the environment used during the observations. At high temperature under vacuum or in an inert atmosphere, the migration of Co atoms towards the core of the particles is activated and leads to the formation of carbon nanostructures using as a template the initial multipods morphology. In the case of reactive environments, for example, pure oxygen, our investigation allowed to directly monitor the voids formation through the Kirkendall effect. Once the nanostructures were oxidised, it was possible to reduce them back to the metallic phase using a dihydrogen flux. Under a pure hydrogen atmosphere, the sintering of the whole structure occurred, which illustrates the high reactivity of such structures as well as the fundamental role of the present ligands as morphology stabilisers. The last type of environmental study under pure CO and syngas (i.e. a mixture of H :CO = 2:1) revealed the metal particles carburisation at high temperature.

show abstract

Section: Introductionmentioning

confidence: 99%

Reactivity and structural evolution of urchin‐like Co nanostructures under controlled environments

Dembélé

Moldovan

Hirlimann

et al. 2017

Journal of Microscopy

View full text Add to dashboard Cite

show abstract

“…Therefore, distinct SHG response can help us distinguish between WZ and ZB crystal structures in single-crystalline materials and enables SHG polarimetry technique to characterize materials such as II−VI and III−V semiconductors that exist in both WZ and ZB crystal structures, which influences their physical properties to produce different responses. 24,29,30 In summary, optical SHG polarimetry was utilized to study crystallography of II−VI semiconductor nanostructures while accounting for the light−matter interactions with nanostructures. The SHG response of nanostructures observed for different growth orientations and crystal structures (WZ and ZB) was intrinsically associated with materials' nonlinear tensor and was analyzed to determine the crystallography of these nanomaterials, which also enabled us to differentiate between WZ and ZB crystal structures.…”

mentioning

confidence: 99%

Crystallographic Characterization of II–VI Semiconducting Nanostructures via Optical Second Harmonic Generation

et al. 2015

Self Cite

View full text Add to dashboard Cite

We demonstrate the utility of optical second harmonic generation (SHG) polarimetry to perform structural characterization of noncentrosymmetric, single-crystalline II-VI semiconducting nanowires, nanobelts, and nanoflakes. By analyzing anisotropic SHG polarimetric patterns, we distinguish between wurtzite and zincblende II-VI semiconducting crystal structures and determine their growth orientation. The crystallography of these nanostructures was then confirmed via transmission electron microscopy measurements performed on the same system. In addition, we show that some intrinsic material properties such as nonlinear coefficients and geometry-dependent optical in-coupling coefficients can also be determined from the SHG experiments in WZ nanobelts. The ability to perform SHG-based structural characterization and crystallographic study of II-VI semiconducting single-crystalline nanomaterials will be useful to correlate structure-property relationships of nanodevices on which transmission electron microscopy measurements cannot be typically performed.

show abstract

“…The time resolution also allowed scientists to witness the growth of nanocrystal and nanomaterial at the atomic scale . Other effects such as material reconstruction or particles sintering and ripening where successfully evidenced by environmental TEM.…”

Section: Environmental Transmission Electron Microscopymentioning

confidence: 99%

In Situ Microscopy and Spectroscopy Applied to Surfaces at Work

et al. 2015

View full text Add to dashboard Cite

The present review discusses the current state of the art microscopic and spectroscopic characterization techniques available to study surfaces and interfaces under working conditions. Microscopic techniques such as environmental transmission electron microscopy and in situ transmission electron microscopy are first discussed showing their applications in the field of nanomaterials and catalysis. Next sum frequency generation vibrational spectroscopy is discussed, giving probing examples of surface studies in gaseous conditions. Synchrotron based X‐ray techniques are also examined with a specific focus on ambient pressure X‐ray photoelectron and absorption techniques such as near and extended X‐ray absorption fine structure. Each of the techniques is evaluated, whilst the pros and cons are discussed in term of surface sensitivity, spatial resolution and/or time resolution. The second part of the articles is articulated around the future of in situ characterization, giving examples of the probable development of the discussed techniques as well as an introduction of emerging tools such as scanning transmission X‐ray microscopy, ptychography, and X‐ray photon correlation spectroscopy.

show abstract

Real-Time Observation of Morphological Transformations in II–VI Semiconducting Nanobelts via Environmental Transmission Electron Microscopy

Cited by 14 publications

References 33 publications

Reactivity and structural evolution of urchin‐like Co nanostructures under controlled environments

Reactivity and structural evolution of urchin‐like Co nanostructures under controlled environments

Crystallographic Characterization of II–VI Semiconducting Nanostructures via Optical Second Harmonic Generation

In Situ Microscopy and Spectroscopy Applied to Surfaces at Work

Contact Info

Product

Resources

About