The Coulomb fragmentation phenomenon has been known to occur in matter at various different length scales, such as nuclei and atomic or molecular clusters, and microscopic droplets. In many cases, the Coulomb explosion is triggered by sudden ionization with high-intensity (>10²14 W/cm¹2) femto-second laser pulses. At this intensity level, the valence electrons are quickly ripped off and the ionized metal clusters fragment before thermalization occurs. In this thesis, we report Coulomb explosion of Ag atoms induced by electron impact ionization in a Si metal-oxide-semiconductor (MOS) structure (Ag/SiO2/Si). Under positive voltage pulses applied to the Ag gate, kinetic electrons are injected onto the gate through leakage channels formed in oxide and impact-ionize the metal atoms at the gate/dielectric interface. When the Coulomb repulsion among the ions becomes stronger than the binding force of metal atoms, the ions accumulated at the interface explode, atomizing the metal and also adjacent dielectrics. This explosive fragmentation results in atomic luminescence from neutral silver at 328 nm, 338 nm, 521 nm, 547 nm, 769 nm, and 827 nm. The mechanisms of oxide breakdown, localized injection of kinetic electrons, and atomization/luminescence are discussed
