Low-Temperature Plasma-Assisted Growth of Core–Shell GeSn Nanowires with 30% Sn

We report on the growth of Sn-catalyzed GeSn nanowires (NWs) having a GeSn core and a c-Ge shell in the presence of germane plasma at substrate temperatures ( T S ) below the GeSn eutectic temperature ( T E ), containing an exceptional Sn concentration of 30 at. % in their core. The differences between the NWs produced at T S above and below T E of the GeSn alloy are highlighted. Two types of NW growth process are identified: the previously reported in-plane solid–liquid–solid (IPSLS) process for T S ≥ T E and a plasma-assisted IPSLS (PA-IPSLS) method taking place at T S < T E; the crucial role of plasma in providing the energy necessary to melt the Sn catalyst at substrate temperatures lower than T E is discussed. The thermal activation window for each method is determined. The PA-IPSLS process is shown to provide an efficient strategy for the growth of crystalline GeSn NWs with a high Sn incorporation in a growth duration of less than 3 min.