pISSN 0374-4914 eISSN 2289-0041

## Research Paper

New Phys.: Sae Mulli 2018; 68: 939-944

Published online September 28, 2018 https://doi.org/10.3938/NPSM.68.939

## Calculation of the Secondary Electron Emission Coefficients of MgO, MgBeO, MgCaO, MgSrO and MgBaO Induced by Auger Neutralization of He$^+$, Ne$^+$, Ar$^+$ and Xe$^+$ Ions

Jong Wan LEE*

Department of Physics, Hallym University, Chuncheon 24252, Korea

Correspondence to:jwlee@hallym.ac.kr

Received: August 7, 2018; Revised: August 22, 2018; Accepted: August 22, 2018

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

### Abstract

In previous experiments, the secondary electron emission (SEE) coefficients, $\gamma$'s, for MgO, MgSrO and MgCaO thin films deposited by using electron beam evaporation were investigated using a gamma focused-ion-beam system. The order of the SEE coefficients of the thin films was $\gamma^{\rm MgO}$ < $\gamma^{\rm MgSrO}$ < $\gamma^{\rm MgCaO}$. We theoretically calculated the SEE coefficients of MgO, MgBeO, MgCaO, MgSrO and MgBaO induced by Auger neutralization of He$^+$, Ne$^+$, Ar$^+$ and Xe$^+$ ions by using the Mathematica code, wihch was developed to calculate those coefficients. In order to get the width of the valence band and the band gap of the materials, we performed a first-principles quantum-mechanical calculation. The calculated order of the $\gamma$'s was $\gamma^{\rm MgBeO}$ < $\gamma^{\rm MgO}$ < $\gamma^{\rm MgCaO}$ < $\gamma^{\rm MgSrO}$ < $\gamma^{\rm MgBaO}$ for all ions. The SEE coefficients of MgCaO and MgSrO were greater than that of MgO. MgCaO and MgSrO, however, showed reverse order. This may be due to the fact that the MgCaO thin film has a polycrystalline structure whereas MgSrO has no crystalline structure.

Keywords: Auger neutralization, Secondary electron emission, MgO, MgBeO, MgCaO, MgSrO, MgBaO