Low-Field Electron Emission from Metallic Nanodots on Oxidized Silicon

Experiments have demonstrated that thin discontinuous Mo films deposited on oxidized Si wafers may possess the capability of low-field electron emission. For different samples with effective thickness 2–6 nm the emission threshold (macroscopic electric field) varied between 3.0 and $6.5\ \mathbf{V}/\boldsymbol{\mu} \mathbf{m}$. Titanium films having similar parameters showed to be incapable of emission field magnitudes $\sim 10\ \mathbf{V}/\boldsymbol{\mu} \mathbf{m}$. Results of AFM and SEM studies allowed us to associate this difference with different morphology of the deposited films. Films of Mo were comprised by separated irregular islands with 5–10 nm height and lateral sizes of tens of nanometers. Films of Ti were also discontinuous but consisted of larger domains having distinctly dendritic structure. These new findings are in good agreement with the results of previous studies performed with carbon island films.