Silver nanoparticle formation in thin oxide layer on silicon by silver-negative-ion implantation for Coulomb blockade at room temperature

Electron field emission properties of Co quantum dots in SiO2 matrix synthesised by ion implantation

“…However, two steps staircase-like I-F characteristics of two steps are observed in the two highest dose samples (5 and 7×10 16 Co + /cm 2 ) and are repeatable in the three successive measurements as shown Fig. 3.…”

“…According to static SRIM simulation [13], the projected range of 50 keV Co + ions in a 150 nm-thick SiO 2 layer on a Si substrate is found to be 43 nm. The doses ranged from 1×10 16 Co + /cm 2 to 7×10 16 Co + /cm 2 and were confirmed by Rutherford backscattering spectrometry (RBS) measurements, with a 1.56 MeV 4 He + beam. The surface morphology was studied using atomic force microscopy (AFM).…”

“…The width of staircase is roughly constant, and, is determined to be values of 1.5 and 5.0 V/µm for the samples with doses of 5 and 7×10 16 Co + /cm 2 , respectively. The staircase current-voltage (IV) characteristics are observed in the metal implanted SiO2 layers even at room temperature attributed to the Coulomb blockage effect arising from the metal quantum dots [16]. Moreover, staircase I-F characteristics are theoretically predicted for the metal quantum dots [17].…”

“…The root-mean-square (rms) values of surface roughness were determined to 0.4, 0.4, 0.2 and 0.5 nm for the samples with doses of 1, 3, 5 and 7×10 16 Co + /cm 2 , respectively. Hence, the geometric local field enhancement effect is negligible in these samples.…”

“…4. The FN plots of the sample with a dose of 3×10 16 Co + /cm 2 can be divided into 3 line segments and saturation in emission current at field strength between 70 and 96 V/µm observed in Fig 3 (a). The presence of three line segments in FN plots are commonly observed in carbon nanotubes and possibly can be explained by space charge effects or surface adsorbate effects [15].…”