Escape depth of secondary electrons induced by ion irradiation of submicron diamond membranes

Abstract

The emission of secondary electrons from any material is governed by electron excitation in the bulk, their transport to the surface, and their escape through the surface into the vacuum. Here, we address the question of the transport of electrons in polycrystalline diamond and amorphous carbon membranes and discuss the factors that limit it. The results of the measurements of the escape depth of the secondary electrons from the membranes of submicron polycrystalline diamond and amorphous carbon films induced by the hydrogen ion impact are reported here. It is found that the escape depth for the secondary electrons emitted from diamond scales with the grain size of the crystallites in the polycrystalline diamond films and it can be very large. In contrast, for the case of the amorphous carbon membranes, we find this depth to be much shorter. The extremely high electron emission yield, which have been measured following the slowing down of the electrons or ions in diamond, can be explained by the fact that secondary electrons can move rather freely in diamond, hence, can reach the surface from large distances inside the diamond sample.

The Impact of Diamond Grain Size on Hydrogen Concentration, Bonding Configuration, and Electron Emission Properties of Polycrystalline‐Diamond Films

“…This sensitivity of the HREEL spectrum of nanodiamond compared to microcrystalline diamond is speculated to be associated with the shorter elastic mean free path of the scattered electrons in the former. [87] This is expected, considering the larger density of internal grain boundaries in the nanometer size grain films compared to the micrometer size ones. The shorter mean free path will result in a larger elastic backscattering cross-section, and thus an enhancement of the losses associated with the subsurface region in the case of nanodiamond-as indeed is observed; the relative intensity of the 155 meV mode (and 300 meV) compared to the $360 meV mode is larger for nano-than that for microcrystalline diamond.…”

Hydrogen concentration and bonding configuration in polycrystalline diamond films: From micro-to nanometric grain size

“…This sensitivity of the HR-EEL spectrum of nanodiamond compared to that of microcrystalline diamond is speculated to be associated with the shorter elastic mean free path of the scattered electrons in the former. 63 This is expected considering the larger density of internal grain boundaries in the nanosized grain films compared to that of the micron-size FIG. 7.…”

Point Defects Creation by Swift Heavy Ion Irradiation Induced Low Energy Electrons in YBa[sub 2]Cu[sub 3]O[sub 7−y] through Dissociative Recombination

“…The secondaries thus formed lose their energies in various types of collision so that only a fraction of them may leave the target if the solid surface is within the range (~10 nm) of these electrons and if they have enough energy to overcome the surface potential barrier [3]. A number of studies have been devoted to determine the number of SEs that are emitted per single ion impact, their energy and angular distribution etc [4]. The SEs, not ejected out, but left behind in the solid are of very low energy and are not known to create lattice disorder.…”