VISIBLE-LIGHT EMISSIONS AND SINGLE-ELECTRON TUNNELING FROM SILICON QUANTUM DOTS EMBEDDED IN SI-RICH SIO2 DEPOSITED IN PLASMA PHASE

Visible photoluminescence at room temperature was observed in silicon- rich oxide films deposited by an electron cyclotron resonance plasma w ith a mixture of silane and oxygen. The photocurrent measurement also exhibits evidence of stable luminescence at 3.0- and 2.2-eV bands from the silicon-enriched parts of oxide films. The emission energy range corresponds to a crystallite size of 10-35 Angstrom. A m odel of the q uantum dot is suggested from an infrared spectroscopic measurement of the chemical bond structures of oxide films. The stable light emission s from both the as-deposited and the rapid thermal annealed samples ar e related to the oxygen passivation of grain boundaries in the Si nano crystallites. The current-voltage measurement for Si-rich oxides shows discontinuous currents around zero voltage at room temperature. The j ump of the conductance relates to the Coulomb blockade in the array of Si quantum dots.