Zinc-Blende GeC Stabilized on GaN (001): An Ab Initio Study

J H Camacho-García,J C Moreno-Hernández,E Chigo-Anota,M Salazar-Villanueva,G Hernández-Cocoletzi,A Bautista-Hernández,Ma L Ruiz-Peralta,A Escobedo-Morales

doi:10.1155/2022/1506702

J H Camacho-García, J C Moreno-Hernández + Show 6 more

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https://doi.org/10.1155/2022/1506702

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Abstract

First-principle calculations have been performed to explore the initial stages of the zinc blende-like germanium carbide epitaxial growth on the gallium nitride (001)-(2 × 2) surface. First, we studied the Ge/C monolayer adsorption and incorporation at high symmetry sites. Results show that the adsorptions at the top and hcp1 sites are the most stable structures of C and Ge, respectively. Different terminated surfaces were used on the GeC epitaxial growth. According to the surface formation energies, only the first two bilayers are stable; therefore, the GeC epitaxial growth is favorable only under N-rich conditions on a Ge-terminated surface and with Ge bilayers terminated. In addition, it is demonstrated that GeC bilayers on the C-terminated surfaces are unstable and preclude the epitaxial growth. Electronic properties have been investigated by calculating the density of states (DOS) and the projected density of states (PDOS) of the most favorable structures.

Highlights

Germanium carbide (GeC) structures have attracted considerable interest because of the extensive applications in optoelectronic devices
Amorphous films have been fabricated by radio frequency (RF) reactive sputtering; the refractive index varied according to the synthesis conditions, an important feature in designing antireflection coatings [6]. eoretical calculations have been developed to investigate the structural, electronic, optical, and magnetic properties of GeC
Exchange-correlation interactions are approximated with the generalized gradient approximation (GGA), as stated in the Perdew–Burke–Ernzerhof (PBE) parametrization [41]. e electron-ion interactions are treated according to the pseudopotential approach, employing Vanderbilt ultrasoft pseudopotentials [42]

Summary

Introduction

Germanium carbide (GeC) structures have attracted considerable interest because of the extensive applications in optoelectronic devices Because they exhibit a narrow optical bandgap, they may be used in photovoltaic and infrared optical devices due to the low stress, tuned refractive index, and high absorption coefficient. First-principle calculations based on the density functional theory (DFT) have been applied extensively due to the versatility to study different materials in order to calculate electronic, optical, and magnetic properties. In this regard, DFT calculations suggest that GexC1 − x thin films possess tunable bandgap [1,2,3,4,5]. In the 2D-GeC system, in both substituted Ge sublattice (VGe@ Ni) or C sublattice (VC@Ni), the distributions of magnetic moments are centered on Ni and the nearest Ge/C atoms [8]

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