Scanning tunneling microscope study of nanosized metal–semiconductor contacts between ErSi2 nanoislands and Si(001) substrate

Theoretical and experimental investigations of nano-Schottky contacts

“…Some experimental and theoretical analyses have been made to investigate the nano M-S contacts. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The analyses have addressed the effect of the nano contact size on the depletion width and on other interface parameters. It was reported that I-V characteristics showed an enhanced current in the reverse bias, which can be attributed to the enhancement of the electric field at the nano M-S interface due to the confined electric charge on a very small metal surface area.…”

Suppressing Effects of Ag Wetting Layer on Surface Conduction of Er Silicide/Si(001) Nanocontacts

“…[22] Our previous investigations verified that this reconstructed surface could provide a remarkable contribution of surface current to the 𝐼-𝑉 curves. [15] In this work, the obtained 𝐼-𝑉 curves indicate that the Ag layer can make the surface electrical conduction path cease to be in effect on the samples of ErSi 2 nanoislands/Si(001). Ag atoms are known not to diffuse into the Si substrate with a low solid solubility, and the saturation coverage of Ag (2 × 3) and 𝑐(6 × 2) reconstructions is 0.50-0.67 ML.…”

“…These electrical transport behaviors were observed in our previous works and were attributed to the effects of surface-state conduction and surface barrier conduction. [10,15] The 𝐼-𝑉 curves in Fig. 3 also exhibit distinctly the dependence on Ag coverage, although the curves are obtained separately on four nanocontacts.…”

“…The current-voltage (𝐼-𝑉 ) characteristics of the nanocontacts between ErSi 2 nanoislands and Si(001) were measured by penetrating the tip directly into the silicide nanoislands with the feedback loop switched off and then ramping the sample bias. [15] The Er silicide nanoislands in the shape of a truncated pyramid (as shown in the inset of Fig. 1) have the base area in the range of 400-18000 nm 2 , with the heights in the range of 7-10 nm.…”

“…To obtain a reliable electrical contact between the STM tip and silicide nanoisland, the dependence of current 𝐼 on the penetration depth ∆𝑧 was investigated before the 𝐼-𝑉 measurements with/without the Ag layer. [15] Here ∆𝑧 is the displacement of the STM tip toward the nanoisland surface, and the zero point of ∆𝑧 is determined by the STM feedback condition. Figure 1 displays a typical relationship between 𝐼 and ∆𝑧 at a constant bias voltage.…”