Defect Modulated Band Modification in Ion Implanted MgO Crystal: Experimental and Ab Initio Calculations

TL;DR

This study investigates how MeV Ni ion irradiation creates defect states in MgO crystals, modifying their optical bandgap, with experimental spectra and DFT calculations revealing potential applications in resistive memory devices.

Contribution

It combines experimental optical spectroscopy with ab initio DFT calculations to elucidate defect-induced bandgap modifications in ion-irradiated MgO.

Findings

Defect states such as F, F2, and vacancies are confirmed via spectra.

Optical bandgap varies with Ni ion fluence.

DFT explains electronic structure evolution due to defects.

Abstract

Defects creation and annihilation is a fundamental concept in device fabrication. This report studies the optical bandgap modification in MgO by MeV Ni ion irradiation-induced defect states between valance and conduction band. Ion implantation on MgO single crystal produces substitutional defect states along with F (anionic vacancy center), $F_2$, other oxygen vacancy center and V (cationic vacancy center) centers confirmed from absorption and photoluminescence spectra that can be applied as filament in valance charge memory based resistive random access memories. The variation of optical bandgap with Ni ion fluences is ascertained by modifying the electronic band structure. Density Functional Theory (DFT) calculation assists in understanding the evolution of electronic band structure for vacancies and substitutional defects consisting of MgO structures.