Growth and structure evolution of novel tin oxide diskettes

The novel SnO diskettes have been synthesized by evaporating either SnO or SnO2 powders at elevated temperature. Disregard the source material being SnO or SnO2, the SnO diskettes are formed at a low-temperature region of 200-400 degreesC. Two types of diskette shapes have been identified: the solid-wheel shape with a drop center rim (type 1) and the diskette with cone peak(s) and spiral steps (type 11). The diskettes are determined to be tetragonal SnO structure (P4/nmm), with their flat surfaces being (001). The formation of the SnO diskettes is suggested to result from a solidification process. The structural evolution from SnO diskettes to SnO2 diskettes has been investigated by oxidizing at different temperatures. The result shows that the phase transformation from SnO to SnO2 occurs in two processes of decomposition and oxidization, and the decomposition process consists of two steps: first from SnO to Sn3O4 and then from Sn3O4 to SnO2.