Single-electron tunneling through Si nanocrystals dispersed in phosphosilicate glass thin films

Electrical transport properties of extremely thin phosphosilicate glass (PSG) films containing Si nanocrystals (nc-Si) a few nanometers in diameter were studied. Samples were prepared by cosputtering Si and PSG targets, and post annealing. Periodic Coulomb staircases were clearly observed in the dc current–voltage $\mathrm{(I–V)}$ characteristics along the vertical direction of films. Although the step structure was broadened with increasing the temperature, it remained up to 200 K. The $\mathrm{I–V}$ curve could be well fitted by Monte Carlo simulation with a simple double-barrier structure model. Advantages of using PSG instead of ${\mathrm{SiO}}_2$ as surrounding matrices of nc-Si to observe single-electron tunneling effects are discussed.