Cd_0.75Sr_0.25F₂: A Potential Dielectric Layer for GaP Based Metal-Insulator-Semiconductor Structures

International Journal of Material Science and Engineering

© 2024 by SSRG - IJMSE Journal

Volume 10 Issue 1

Year of Publication : 2024

Authors : Alice Bukola Olanipekun, Olumide Idowu Akasoro

10.14445/23948884/IJMSE-V10I1P102

How to Cite?

Alice Bukola Olanipekun, Olumide Idowu Akasoro, "Cd_0.75Sr_0.25F₂: A Potential Dielectric Layer for GaP Based Metal-Insulator-Semiconductor Structures," SSRG International Journal of Material Science and Engineering, vol. 10,  no. 1, pp. 6-12, 2024. Crossref, https://doi.org/10.14445/23948884/IJMSE-V10I1P102

Abstract:

Cd_0.75Sr_0.25F₂ is a mixed alloy that has the potential to function as an insulating layer in metal insulator semiconductor (MIS) systems. A theoretical investigation of the structural and dielectric properties of Cd_0.75Sr_0.25F₂ and its binary fluorides (CdF₂ and SrF₂) is reported utilizing the Pseudopotential Plane-Wave (PP-PW) approach in Density Functional Theory (DFT) and Density Functional Pertubation Theory (DFPT). For the exchange-correlation (XC) potentials, this method employs the generalized gradient approximation (GGA). The binary compounds’ and alloy’s lattice constant, bulk modulus, refractive index, static dielectric constant, band gap, intrinsic breakdown field, energy density, storage density, and lattice misfit are all reported. The estimated lattice constants agreed with the experimental data. The bulk modulus for SrF₂ is consistent with experimental results. The computed bulk modulus of Cd_0.75Sr_0.25F₂ (87.6GPa) shows it is moderately hard. The intrinsic breakdown field depends on the band gap, while the energy storage density depends on the band gap and dielectric constant. A linear relationship is obtained between the intrinsic breakdown field and band gap of considered fluorides and oxides. The intrinsic breakdown field increases in the order HfO₂—CdF₂— Cd_0.75Sr_0.25F2—SiO₂—SrF₂ while the energy density increases in the order HfO₂—SiO₂— CdF₂—SrF₂— Cd_0.75Sr_0.25F₂. The predicted band gap and dielectric constant of Cd0.75Sr0.25F2 are 8.19eV and 8.714, respectively. The intrinsic breakdown field of Cd0.75Sr0.25F2 is 2.78V/nm. Its energy storage density is 299.13J/cm3 . There is an improvement in the values of dielectric constant and energy storage density for Cd_0.75Sr_0.25F₂ when compared with SiO₂. These properties of Cd_0.75Sr_0.25F₂ make it a potential insulating layer for MIS devices. From the calculation of lattice mismatch, Cd_0.75Sr_0.25F₂ and CdF₂ have a mismatch of <1%, which makes them suitable dielectric layers on the Gallium Phosphide (GaP) substrate.

Keywords:

DFT, DFPT, Dielectric constant, Insulating layer, Intrinsic breakdown field, Energy storage density.

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