Abstract text (incl. figure legends and references)

EBSD analysis on beam sensitive and nanostructured materials demands in many cases low-kV, low-dose or low-vacuum operation with careful beam budget design and sensitive detectors in order to avoid sample degradation, minimize image drift, satisfy spatial resolution requirements and gain sufficient signal-to-noise level for indexable Kikuchi patterns [1-3]. The stated requirements play a major role for the structural characterization of metal-halide-perovskite (MHP) thin films/crystallites, which revolutionized the field of thin-film semiconductor technology, due to their favorable optoelectronic properties and facile solution processing e.g. by inkjet-printing [4]. Best device efficiencies require structural coherence on the atomic scale, which can be achieved by epitaxial growth on lattice matching substrates [4]. In this work, we demonstrate the capability of recent sensitive EBSD cameras for the structural characterization of beam sensitive MHP crystallites (CsPbBr₃, FACsPbBr₃, MAPbBr₃) grown on various substrates (PbS, mica). In particular new direct detection based cameras allow to obtain indexable Kikuchi patterns from MHPs at strongly decreased electron dose at low-kV compared to their indirect detection based counterparts (Figure 1a), which is crucial for a reliable and statistically relevant EBSD characterization. Based on this, we present EBSD results underlining the homogeneous hetero-epitaxial growth over large scale of CsPbBr₃ and FACsPbBr₃ crystallites on single crystalline PbS substrates fabricated via inkjet-printing and further substantiate the theory of lattice-anchoring and stabilization of the cubic crystal structure of MHPs as indicated in former studies [4, 5] (Figure 1b). Further, we present results on the orientation-dependent growth characteristic of FACsPbBr₃ crystallites on flexible and single crystalline mica substrates. Here, various different cubic crystal orientations with characteristic morphologies are observed. Most crystals feature a [101] out-of-plane orientation which is parallel to the [001] axis of the substrate and grow along (110) planes, with a few of them obtaining an in-plane orientation of [101] parallel to the [010] direction of the substrate. Further advantages of low-kV and low-dose sensitive EBSD detectors lie in the achievable spatial resolution, making them perfectly suitable for the analysis of nanomaterials. This benefit evolves particularly in conjunction with low-vacuum operation, since any need for conductive coating of the sample surface, which damps the EBSD signal, but is often required to minimize sample drift, is reduced. Referring to this, we present in Figure 2 EBSD results on the texture analysis on nano-grained and low Z-number thin films (AlN) based on Pt/Ti/SiO2/Si substrates, revealing an average grain size of ~30 nm and a crystal fiber texture with an out of-plane <0001> alignment. Further analyses focus on the local clustering of neighboring grains with similar orientation. Overall, we show that the application of low-kV and low-dose EBSD paves the way for a reliable and efficient structural characterization of beam sensitive and nanomaterials and enables new insights into epitaxial growth and the orientation-dependent growth of MHPs on large scale.

[1] Adhyaksa et al., 10.1002/adma.201804792

[2] Leonhard, et al., 10.1002/ente.201800989

[3] Luo et al., 10.1021/acs.jpcc.0c06733

[4] Sytnyk et al., 10.1002/adfm.202004612

[5] Afify et al., 10.1002/adom.202200237