Growth of ZnSe-based longitudinal twinning nanowires by phase transformation

摘要

Zinc blende ZnSe longitudinal twinning nanowires (Type Ⅰ) and a sandwich structure with the wurtzite ZnSe inserting into the zinc blende ZnSe longitudinal twinning nanowires (Type Ⅱ) are fabricated via a simple thermal evaporation method. The growth of them might be caused by the crystal plane slip during the phase transformation process from wurtzite ZnSe to zinc blende ZnSe nanowire. The wurtzite ZnSe might have two origins: 1) The phase transformed wurtzite from zinc blende. At first, during the temperature rising stage in the experiment, before the temperature approached to the transformation temperature (T_(tr)), ZnSe in zinc blende phase might begin to nucleate and grow. Once the temperature is higher than T_(tr), the zinc blende products would transform to wurtzite phase. 2) The new-born nuclei grown wurtzite phase at high temperature for it is reported that the wurtzite phase is more stable at higher temperature. During the cooling period, the source material is exhausted and no more nucleation would occur. Some of the wurtzite products would transform to zinc blende phase when the temperature is lower than T_(tr). During the process, it is reasonable that the ZB phase begins to form from the outer sides of an individual nanowire. Once the process completes, the longitudinal twinning ZB nanowire would be obtained; otherwise, the sandwich-structured nanowire forms.