Secondary Electron Transmission Studies of the Electron Diffusion and Thermalization Processes in Thin CVD Diamond Films

Abstract

ABSTRACTSecondary electron transmission measurements are used to examine the electron diffusion and thermalization processes in B-doped nanocrystalline diamond membranes of thickness 2.3 μm and 650 nm. Specifically, transmitted energy spectra are measured following impact by an electron beam that penetrates deeper in the membrane as the beam energy Eo increases. A fully-thermalized emission peak is observed for Eo ≤ 16 keV and Eo ≤ 7 keV from the 2.3-μm-thick and 650-nm-thick films, respectively, with a small high-energy tail beginning to emerge at higher Eo. These measurements are analyzed using Monte Carlo simulations that generate constant-energy contour lines (down to 0.05 Eo) as a function of beam depth into the film. From these simulations, we deduce that secondary electrons have a minimum thermalization length of ∼ 630 nm and ∼ 260 nm in the 2.3-μm-thick and 650-nm-thick films, respectively. Further insight into the secondary-electron transport behavior is gained from the analysis, and this understanding is applied to the design of a transmission electron-current amplifier device.