Negative-electron-affinity effect on the surface of chemical-vapor-deposited diamond polycrystalline films

Abstract

ABS1RACT / I;· I.Strong negative electron affinity effects have been observed on the surface of as-grown chemical vapor deposited diamond using Secondary Electron Emission. The test samples were randomly oriented and the surface was tenninated with hydrogen. The effect appears as an intensive peak in the low energy part of the spectrum of the electron energy distribution and may be described in the model of effective negative electron affinity.One of the remarkable features of diamond ~s the negative electron affinity (NEA) that may be observed on its surface under specific conditions. llO For NEA the vacuwn energy level lies below the conduction band minimum which allows electrons to escape easily from the surface.11 Semiconductors with NEA are widely used as photo-and cold-cathode emitters.NEA from diamond has been shown to correspond with the presence of hydrogen bounded to the surface.

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

“…3, spectrum A) is shifted to 1420 cm À1 (Fig. 3, spectrum B) when 12 C was replaced by 13 C. The decrease of the 1332 cm -1 diamond peak in the Raman spectra of the HFCVD diamond films due to isotopic exchange of H by D indicates that the crystalline quality of these films deteriorated due to the replacement, which modified the deposition conditions, even though the growth parameters were kept intact. This explains why the 1140 cm À1 peak of the high-quality diamond film (highest 1332 cm À1 peak) is very weak.…”

“…The well-known negative electron affinity (NEA) and high conductivity of diamond surfaces are properties of fully hydrogenated diamond surfaces. [12][13][14] Similarly, diamond grain size may influence the electronic and optical properties of the films. [15][16][17][18] The properties and associated practical applications of diamond films are significantly modified by their surface structure and chemical composition.…”

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

“…The well-known negative electron affinity and high conductivity of diamond surfaces are properties of fully hydrogenated diamond surfaces. [12][13][14] Similarly, diamond grain size may influence the electronic and optical properties of the films. [15][16][17][18] The properties and associated practical applications of diamond films are significantly modified by their surface structure and chemical composition.…”

Secondary Emission Enhanced Photoinjector

“…• The energy distribution of the secondary electrons under low electric field is shown to be < 1 eV, centered ~ 4.5 eV above the Fermi energy. This energy distribution is larger than the thermal distribution of the electrons, leading one to conclude that the escape time is smaller [5] than the electron-phonon relaxation time of 10 -12 -10 -13 s [6]. The secondary electrons energy distribution traversing the diamond will be the result of equilibrium.…”