Well-aligned periodic germanium nanoisland arrays with large areas and improved field emission performance induced by femtosecond laser

Si-based field emitters with high and stable current densities have gained increasing attention owing to their relevant compatibility with other silicon-based microelectronic and photonic devices. Currently, well-aligned Ge nanostructure arrays can be used in fabrication of Si-based field emitters with excellent performance. In this study, large-area well-aligned Ge nanoisland arrays are induced by femtosecond laser (120 fs, 800 nm, 1 kHz). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman analyses, and X-ray photoelectron spectroscopy (XPS) reveal that well-aligned Ge nanoisland arrays with good quality. Field emission (FE) measurements indicate Ge nanoisland arrays with high emission current densities and good stability. Overall, the excellent FE properties of the proposed Ge nanoisland arrays will make them potential for applications in high-performance field emitters integrated with Si nanodevices.