Visible and infrared emission from Si/Ge nanowires synthesized by metal-assisted wet etching
1 IPCF CNR, viale F. Stagno d'Alcontres 37, Faro Superiore, Messina 98158, Italy
2 MATIS IMM CNR, via Santa Sofia 64, Catania 95123, Italy
3 Dipartimento di Fisica e Astronomia, Università di Catania, via Santa Sofia 64, Catania 95123, Italy
4 Scuola Superiore di Catania, Università di Catania, via Valdisavoia 9, Catania 95123, Italy
Nanoscale Research Letters 2014, 9:74 doi:10.1186/1556-276X-9-74Published: 12 February 2014
Multi-quantum well Si/Ge nanowires (NWs) were realized by combining molecular beam epitaxy deposition and metal-assisted wet etching, which is a low-cost technique for the synthesis of extremely dense (about 1011 cm−2) arrays of NWs with a high and controllable aspect ratio. In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm. NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures. We performed a detailed study of the photoluminescence properties of the NWs, with particular attention to the excitation and de-excitation properties as a function of the temperature and of the excitation photon flux, evaluating the excitation cross section and investigating the presence of non-radiative phenomena.
61.46.Km; 78.55.-m; 78.67.Lt