Reconstruction of evolving nanostructures in ultrathin films with X-ray waveguide fluorescence holography

Abstract

Controlled synthesis of nanostructure ultrathin films is critical for applications in nanoelectronics, photonics, and energy generation and storage. The paucity of structural probes that are sensitive to nanometer-thick films and also capable of in-operando conditions with high spatiotemporal resolutions limits the understanding of morphology and dynamics in ultrathin films. Similar to X-ray fluorescence holography for crystals, where holograms are formed through the interference between the reference and the object waves, we demonstrated that an ultrathin film, being an X-ray waveguide, can also generate fluorescence holograms as a result of the establishment of X-ray standing waves. Coupled with model-independent reconstruction algorithms based on rigorous dynamical scattering theories, the thin-filmbased X-ray waveguide fluorescence holography becomes a unique in situ and time-resolved imaging probe capable of elucidating the real-time nanostructure kinetics with unprecedented resolutions. Combined with chemical sensitive spectroscopic analysis, the reconstruction can yield element-specific morphology of embedding nanostructures in ultrathin films.

Traceable Characterization of Nanomaterials by X-ray Spectrometry Using Calibrated Instrumentation

“…With respect to nanomaterial development and quality management applications in the semiconductor industry, it is also valuable to take advantage of the optical equivalence With respect to nanomaterial development and quality management applications in the semiconductor industry, it is also valuable to take advantage of the optical equivalence of grazing incidence and grazing emission XRF (GI-and GEXRF) principles. The GEXRF approaches have been successfully explored for more than two decades at various large-scale facilities and in academic laboratories [75][76][77][78][79][80][81], in particular regarding the characterization of nanolayered systems. To complement angular GIXRF studies [22,72] and related reconstruction works on nanostructures [73], GEXRF also allows for the scanning-free detection of the angular distribution of fluorescence radiation emitted by a nanostructure using position-sensitive detectors such as CCDs or CMOS devices [82].…”

“…of grazing incidence and grazing emission XRF (GI-and GEXRF) principles. The GEXRF approaches have been successfully explored for more than two decades at various largescale facilities and in academic laboratories [75][76][77][78][79][80][81], in particular regarding the characterization of nanolayered systems. To complement angular GIXRF studies [22,72] and related reconstruction works on nanostructures [73], GEXRF also allows for the scanning-free detection of the angular distribution of fluorescence radiation emitted by a nanostructure using position-sensitive detectors such as CCDs or CMOS devices [82].…”

Parameter estimation for X-ray scattering analysis with Hamiltonian Markov Chain Monte Carlo

“…XWFH is a recently developed high-resolution probe for atom or nanoparticle depth profiling in thin films. While the principle and experimental considerations are described in detail elsewhere (Jiang et al, 2020), they are briefly illustrated here via an example [Fig. 5(a)].…”

“…Model assessment and selection methods help determine the number of splines N S . In this example, we evaluated models with different N S and found that approximately 30 splines (thus 30 unknown spline coefficients) are required to give a sensible result (Jiang et al, 2020). Assuming no prior knowledge about this profile, we set a constant value for all the initial spline coefficients.…”

Applications of X-Ray Holography

“…In 2011, Kim et al [88] obtained the reconstructed image of nanomaterials with the resolution of 87 nm with single-shot Fourier-transform X-ray holography and X-ray laser. In 2020, Zhang et al [89] reconstructed the evolved nanostructures in ultrathin films with X-ray waveguide fluorescence holography. e analysis results showed that the controllable synthesis of nanostructure ultrathin films may become a reality.…”