Strong Room-Temperature Visible Photoluminescence of Amorphous Si Nanowires Prepared by Electrodeposition in Ionic Liquids

Abstract

Visible photoluminescence at room temperature is reported from the silicon nanowires prepared by electrodeposition in ionic liquids. Nanowires with diameters 110, 200, and 400 nm have been synthesized by a template-assisted electrodeposition using ionic liquid electrolytes. The obtained nanowires are amorphous in nature and possess robustness and good structural and compositional quality. The PL measurements at room temperature reveal a strong visible light emission from the 110 nm silicon nanowires. The strong and efficient red luminescence from the nanowires is found to be size-dependent and originates from the intrinsic radiative recombination and spatial confinement of carriers in the amorphous silicon nanowires with a thin surface oxide shell. The silicon nanowires with 110 nm diameter shows an exceptionally high quantum yield >25%. These light-emitting nanowires obtained through a simple alternative growth technique could find applications in future Si-based optoelectronic devices.

Growth of Homogeneous Luminescent Silicon–Terbium Nanowires by One-Step Electrodeposition in Ionic Liquids

“…SEM analysis (Figure 3a) shows a typical network of Si/Tb NWs, slightly flexible and interconnected. The flexibility of the NWs could be due to their amorphous nature as previously observed for silicon-based NWs or films prepared by electrodeposition [27,32] and confirmed by the electronic diffraction pattern obtained by TEM on a single NW (Figure 3c inset). From the microscopic analysis, the diameters of the NWs are uniform and around 90 nm, which corresponds well to the diameter of the nanopores of the template.…”

“…First, the electrochemical behavior of individual precursors, i.e., SiCl 4 and TbCl 3 , in Py 1,4 [TFSI] was studied by performing their CVs to evidence the possible deposition of the metallic species, and then, an electrolyte solution containing a mixture of these two precursors was analyzed to study the electrochemical feasibility of co-depositing Si and Tb simultaneously. The red and blue curves in Figure 2 [TFSI] are described in our recent reports [31,32], which proves the possibility of depositing Si and Tb in their elemental form. An electrolyte solution containing a mixture of these two precursors was then analyzed by CV.…”

“…50 °C. Details on the electrochemistry of individual precursors in Py1,4[TFSI] are described in our recent reports [31,32], which proves the possibility of depositing Si and Tb in their elemental form.…”

“…It is evident from the CV studies that Si and Tb could be co-deposited as NWs by applying an appropriate potential in Py1 50 °C. Details on the electrochemistry of individual precursors in Py1,4[TFSI] are described in our recent reports [31,32], which proves the possibility of depositing Si and Tb in their elemental form.…”

“…200 nm) was sputtered on one side of the PC membrane to make the electrical contact. More details of the electrochemical experimental setup are explained in our previous report [32]. All the electrochemical potentials mentioned here are referenced to a Pt quasi-reference electrode.…”