Three-dimensional in situ imaging of single-grain growth in polycrystalline In2O3:Zr films

Abstract

Strain and interactions at grain boundaries during solid-phase crystallization are known to play a significant role in the functional properties of polycrystalline materials. However, elucidating three-dimensional nanoscale grain morphology, kinetics, and strain under realistic conditions is challenging. Here, we image a single-grain growth during the amorphous-to-polycrystalline transition in technologically relevant transparent conductive oxide film of In2O3:Zr with in situ Bragg coherent X-ray diffraction imaging and transmission electron microscopy. We find that the Johnson-Mehl-Avrami-Kolmogorov theory, which describes the average kinetics of polycrystalline films growth, can be applied to the single grains as well. The quantitative analysis stems directly from imaging results. We elucidate the interface-controlled nature of the single-grain growth in thin films and reveal the surface strains which may be a driving force for anisotropic crystallization rates. Our results bring in situ imaging with coherent X-rays towards understanding and controlling the crystallization processes of transparent conductive oxides and other polycrystalline materials at the nanoscale.

Imaging Light‐Induced Migration of Dislocations in Halide Perovskites with 3D Nanoscale Strain Mapping

“…The technique has been employed to reveal the 3D atomic displacement fields within ZnO nanorods, [23] to track the evolution of ferroelastic domain walls in barium titanate, [24] and to identify twin domains in CsPbBr 3 nanoparticles. [25] Further, the approach has been used to mon-itor the growth of crystalline grains during the annealing process of In 2 O 3 :Zr thin films, [26] during calcite crystal solution and dissolution, [27] and to track dislocations dynamics in the LiNi 0.5 Mn 1.5 O 4 battery electrode material during charging and discharging. [28] Here, we develop an in situ BCDI approach to visualize the surprisingly rich strain fields within high-quality single microcrystals of halide perovskites and monitor their evolution under continuous solar illumination.…”

Impact of the TCO Microstructure on the Electronic Properties of Carbazole-Based Self-Assembled Monolayers

“…This observed change in crystallinity and microstructure is due to a solid phase crystallization, as previously reported for sputtered In-based TCOs. , In the process of physical vapor deposition of In-based TCOs at room temperature (by either PLD or sputtering), nanocrystals are generated within an amorphous matrix. These nanocrystals act as nucleation sites, facilitating the growth of grains during a subsequent annealing step . Commercially available ITO substrates (Ossila Ltd.), featuring a polycrystalline structure and nanoscale grains microstructure (RMS of 3.20 nm), as depicted in Figure a and e, respectively, were used to compare the influence of the grain size in the WF distribution.…”

“…This observed change in crystallinity and microstructure is due to a solid phase crystallization, as previously reported for sputtered In-based TCOs. 7 , 8 In the process of physical vapor deposition of In-based TCOs at room temperature (by either PLD or sputtering), nanocrystals are generated within an amorphous matrix. These nanocrystals act as nucleation sites, facilitating the growth of grains during a subsequent annealing step.…”

“…These nanocrystals act as nucleation sites, facilitating the growth of grains during a subsequent annealing step. 7 Commercially available ITO substrates (Ossila Ltd.), featuring a polycrystalline structure and nanoscale grains microstructure (RMS of 3.20 nm), as depicted in Figure 1 a and e, respectively, were used to compare the influence of the grain size in the WF distribution. Figure S3 showcases the comparison of three commercially available ITO substrates from different suppliers.…”

“…Depending on the TCO deposition method and process conditions, different microstructures can be achieved which may also influence the optoelectronic properties. For instance, amorphous TCOs generally feature a narrower band gap as compared to polycrystalline TCOs due to their distorted absorption edge. , The electron mobility in TCOs can also be influenced by the microstructure, with typically high mobilities achieved for polycrystalline TCOs with large grains. − …”