Self-limiting stoichiometry in SnSe thin films

Abstract

Raman spectroscopy showing the initial formation of SnSe2 followed by the stabilization of SnSe with increased growth time.

Transition from fractal-dendritic to compact islands for the 2D-ferroelectric SnSe on graphene/Ir(111)

“…As an alternative to evaporation from SnSe powder using a single source used by us, thin films of SnSe have also been grown by co-evaporation of Sn and Se using two effusion cells [44,45]. This method is in principle also applicable for the growth of monolayers.…”

Quasi-Van der Waals Epitaxial Growth of γ′-GaSe Nanometer-Thick Films on GaAs(111)B Substrates

“…Se:Ga flux ratios as low as 1.4 failed to generate continuous GaSe crystal films but produced only isolated, spiral, near-triangular flakes (Figure a). The triangular spiral morphology is characteristic of 2D chalcogenides. − The literature on MBE growth of InSe, a material with an almost identical crystal structure to GaSe, has proposed two possible explanations for the spiral growth: (1) unequal growth rates along the zigzag and armchair edges, in combination with the angle of the initial nuclei relative to substrate step edges, can generate spiral dislocation centers for subsequent growth and (2) the metal vacancies created by the Se-rich growth conditions can introduce localized structural distortions, resulting in islands with zigzag edge fronts climbing over neighboring islands rather than merging into 2D layers. We experimentally observed that appropriately increasing the growth temperature can inhibit spiral growth while simply reducing the Se:Ga flux ratio cannot inhibit the generation of spiral centers, as revealed by Figure a.…”

Review of Nanolayered Post-transition Metal Monochalcogenides: Synthesis, Properties, and Applications

“…Chang et al used high-purity SnSe granule source materials to grow highly oriented SnSe single layers on graphene substrates using a two-step growth and anneal process. SnSe nanoplates have been produced by optimizing the growth and annealing temperatures. ,, Maintaining stoichiometry is critical for the growth of SnSe. Chin et al used individual elemental source materials to study the self-limiting stoichiometry in SnSe and revealed that within a limited range, changing the Se:Sn flux ratio does not influence the film stoichiometry, but only rotates the primary crystallographic orientation from (210) to (200).…”

“…SnSe nanoplates have been produced by optimizing the growth and annealing temperatures. ,, Maintaining stoichiometry is critical for the growth of SnSe. Chin et al used individual elemental source materials to study the self-limiting stoichiometry in SnSe and revealed that within a limited range, changing the Se:Sn flux ratio does not influence the film stoichiometry, but only rotates the primary crystallographic orientation from (210) to (200). By replacing MgO(001) substrates with a-plane sapphire substrates, which have rectangular lattice-matched symmetry that breaks the SnSe domain degeneracy, Mortelmans et al realized SnSe films free of 90° twin defects.…”