Platinum Adsorption and Diffusion on Two-Dimensional Gallium Nitride

Fatih Ersan

doi:10.19113/sdufbed.56851

Abstract

In this study, we examined the adsorption and diffusion of platinum (Pt) adatom on two-dimensional hexagonal gallium nitride (h-GaN), by using first-principles plane-wave calculations. Two different levels of platinum coverage ratio (θ=1/8 and θ=1/32) were considered and the changes in the electronic structure for high-level platinum coverage ratio (θ=1/8) were examined. Low-level coverage ratio (θ=1/32) is used to calculate the diffusion barrier energy of Pt adatom on GaN monolayer. Our theoretical calculations have shown that Pt atom strongly binds on the top of nitrogen atoms in GaN monolayer and high energy is required for its diffusion. While GaN monolayer has 2.1 eV indirect band gap (Γ→K), this band gap reduces to 1.3 eV with Pt adsorption. These results may lead to further investigations on forming Pt nanoparticles or Pt coating on GaN sheet.

Highlights

Gallium nitride (GaN) can be found in cubic zincblende or wurtzite crystal structures
We systematically examine Pt adsorption on hexagonal gallium nitride (h-GaN) monolayer by varying the coverage ratio
After obtaining the optimized structure, adsorption energy of Pt atom on the h-GaN monolayer is calculated from the expression below; E(ads)=E(GaN)+E(Pt)-E(GaN+Pt) where E(GaN) is the total energy of the bare GaN substrate, E(Pt) is an isolated spin-polarized platinum atom energy, and E(GaN+Pt) is the energy of the system of Pt adsorped to the substrate

Summary

Introduction

Gallium nitride (GaN) can be found in cubic zincblende or wurtzite crystal structures. Both of them have a wide band gap in the range of 3.30 – 3.50 eV [1, 2]. Owing to their band gap, GaN structures are the most commonly used semiconductors in optoelectronic device applications, e.g., fabrication of light-emitting diodes (LED) to operate in blue-light and ultraviolet regions, room temperature laser diodes, high temperature/high power electrical devices [3, 4]. In addition to its wide band gap, GaN is a chemically and thermally stable semiconductor material, which preserves its structural stability up to temperatures above 1100K [5].

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Conclusion