Electron-beam induced synthesis of nanostructures: a review

Abstract

As the success of nanostructures grows in modern society so does the importance of our ability to control their synthesis in precise manners, often with atomic precision as this can directly affect the final properties of the nanostructures. Hence it is crucial to have both deep insight, ideally with real-time temporal resolution, and precise control during the fabrication of nanomaterials. Transmission electron microscopy offers these attributes potentially providing atomic resolution with near real time temporal resolution. In addition, one can fabricate nanostructures in situ in a TEM. This can be achieved with the use of environmental electron microscopes and/or specialized specimen holders. A rather simpler and rapidly growing approach is to take advantage of the imaging electron beam as a tool for in situ reactions. This is possible because there is a wealth of electron specimen interactions, which, when implemented under controlled conditions, enable different approaches to fabricate nanostructures. Moreover, when using the electron beam to drive reactions no specialized specimen holders or peripheral equipment is required. This review is dedicated to explore the body of work available on electron-beam induced synthesis techniques with in situ capabilities. Particular emphasis is placed on the electron beam-induced synthesis of nanostructures conducted inside a TEM, viz. the e-beam is the sole (or primary) agent triggering and driving the synthesis process.

In Situ Transmission Electron Microscopy Study of Electron Beam-Induced Transformations in Colloidal Cesium Lead Halide Perovskite Nanocrystals

“…28 Knock-on damage involves an irreversible displacement of the nuclei in the specimen, when the transferred energy overcomes the displacement energy of the atoms in the material, and it is dominant at high energy. 26,28,29 Ionization damage (or radiolysis) involves inelastic scattering, and is dominant at low energy. 28,29 In the present case, for a better comprehension of the electron-specimen interaction we evaluated the evolution of halide perovskite NCs, which involved appreciable compositional change, upon electron beam irradiation at two different values of incident electron energy ( E 0 ) (see Figure S1).…”

“…Such loss of Br atoms is analogous to the electron stimulated desorption of fluorine in CaF 2 , or of oxygen in several oxides, as said before. 26 In the case of CaF 2 , F – is oxidized to F 0 or to F + , and likewise in oxides O 2– is oxidized to O 0 or to O + . The neutral species (F 0 or O 0 ) diffuse and are desorbed due to their low reactivity.…”

Nanoscale Lacing by Electrons

“…Here we report an intriguing finding of the morphological evolution from the aligned Au(I)‐thiolate motifs to Au NCs under electron beam from scanning transmission electron microscopy (STEM), revealing an unprecedented string assembly of monodispersed NCs ranging from sub‐nm to ≈1 nm. This finding stems from the basic concept that the electron beam functions as the sole agent which is capable of triggering and driving the nanoscale reactions in situ . Indeed, the formation of Au NPs of 2 and 5 nm sizes from Au(I)‐SR under electron beam irradiation from high‐dose transmission electron microscopy (TEM) source was previously demonstrated .…”

Single-atom fabrication with electron and ion beams: From surfaces and two-dimensional materials toward three-dimensional atom-by-atom assembly

“…This area was actively explored in the 1980s and 1990s, and e-beam crystallization of a number of important semiconductors such as Si [49][50][51][52] and GaAs [52][53][54] has been reported. Similarly, the beam can result in selective removal of material, and when integrated with beam-induced reactions, it can enable fabrication of nanoscale structures, as summarized in recent reviews by Krasheninnikov,55 Gonzales-Martinez, 56 and Jesse. 57 The associated mechanisms are discussed by Jiang.…”