Comparison of hot-electron transmission in ferromagnetic Ni on epitaxial and polycrystalline Schottky interfaces

TL;DR

This study compares hot-electron transmission in Ni across epitaxial and polycrystalline Schottky interfaces, revealing similar attenuation lengths despite differences in interface transmission, highlighting the role of inelastic scattering and interface properties.

Contribution

It provides the first direct comparison of hot-electron attenuation in Ni on epitaxial versus polycrystalline interfaces using BEEM.

Findings

BEEM transmission is lower for polycrystalline interface.

Attenuation length in Ni is the same for both interfaces.

Inelastic scattering and interface transmission dominate hot-electron attenuation.

Abstract

The hot-electron attenuation length in Ni is measured as a function of energy across two different Schottky interfaces viz. a polycrystalline Si(111)/Au and an epitaxial Si(111)/NiSi_2 interface using ballistic electron emission microscopy (BEEM). For similarly prepared Si(111) substrates and identical Ni thickness, the BEEM transmission is found to be lower for the polycrystalline interface than for the epitaxial interface. However, in both cases, the hot-electron attenuation length in Ni is found to be the same. This is elucidated by the temperature-independent inelastic scattering, transmission probabilities across the Schottky interface, and scattering at dissimilar interfaces.