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.