Si Wires in Silicon-On-Insulator Configuration

We propose a systematic investigation of crystalline Si structures as their dimensions are reduced to quantum sizes (5-10 nm). For convenience, we have chosen Si on insulator (SOI) material for optical and electrical characterization. Our nanofabrication approach relies on simple laser interferometric lithography techniques that are uniquely adaptable to large area manufacturing. Suitable application of wet-chemical etching and steam oxidation of Si have been used to form free-standing Si wires. SEM, Raman, PL, and electrical measurements are used to characterize Si wires as a function of their linewidth. Raman scattering shows large enhancement for 50-100 nm linewidths, and a splitting of the bulk mode for estimated 10-nm linewidths. Room temperature PL measurements from 10-nm structures show peaks varying from 530-630 nm. Electrical measurements in MSM configuration show significantly enhanced current response. A systematic investigation of these nm wire structures is proposed to determine PL correlation with crystal-size, and device performance in MSM and pn-junction configurations. Commercial applications include: 1. Si light sources for display applications, optical interconnects, 2. Si field-emission devices, 3. nm-linewidth Si devices, and 4. Si grating solar cells.