Non‐Steady‐State Symmetry Breaking Growth of Multilayered SnSe2 Nanoplates

The use of non‐equilibrium growth modes with non‐steady dynamics is extensively explored in bulk materials such as amorphous and polycrystalline materials. Yet, research into the non‐steady‐state (NSS) growth of two‐dimensional (2D) materials is still in its infancy. In this study, multilayered tin selenide (SnSe2) nanoplates are grown by chemical vapor deposition under NSS conditions (modulating carrier gas flow and temperature). Given the facile diffusion and inherent instability of SnSe2, it proves to be an apt candidate for nucleation and growth in NSS scenarios. This leads to the emergence of SnSe2 nanoplates with distinct features (self‐growth twisting, symmetry transformation, interlayer decoupling, homojunction, and large‐area 2D domain), exhibiting pronounced second harmonic generation. The authors’ findings shed light on the growth dynamics of 2D materials, broadening their potential applications in various fields. Multilayered SnSe2 nanoplates, grown via chemical vapor deposition under non‐steady‐state conditions, display distinct symmetry‐breaking structures and enhanced second harmonic generation.