Stabilization of diamond cubic Sn nanodots in Ge

Abstract Diamond cubic Sn (α-Sn) has many potential optoelectronic applications, but is normally stable only below 13°C. Here we demonstrate the stabilization of α-Sn nanodots at room temperature and above in a Ge matrix produced by rapid solidification of a Ge-6.3 at%Sn alloy. High resolution transmission electron microscopy (HRTEM) and differential scanning calorimetry (DSC) were employed to study the structure and stability of Sn particles, respectively. We show that the formation pathway of α-Sn is through the decomposition of a Ge-Sn solid solution, which gives a thermodynamic driving force necessary for the formation of α-Sn.