Large scale SnSe pyramid structure grown by gradient vapor deposition method

Due to the novel properties distinguished from their bulk counterparts, the two-dimensional layered materials have attracted great interest recently. In this report, the SnSe pyramid structure was successfully synthesized using the gradient vapor deposition method developed herein. The SnSe pyramid structure was grown by layered stacking along the a-axis by van der Waals forces in which shrinkage occurred gradually from the bottom to the tip. Furthermore, an Sn nanoparticle was found in the tip and suggested to be the catalyst to grow the nanostructure; then, a growth mechanism was proposed based on the results mentioned above. As an ideal model, the SnSe pyramid structure was applied in Raman spectroscopy to identify the crystal orientation. The results mentioned here may provide a valuable guidance to design a unique SnSe nanostructure even with other 2D layered materials.