Determination of Band Structure of Gallium-Arsenide and Aluminium-Arsenide Using Density Functional Theory
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-01-01 |
| Journal | Computational Chemistry |
| Authors | J. A. Owolabi, M. Y. Onimisi, S.G. Abdu, G.O. Olowomofe |
| Institutions | Kaduna State University, Nigerian Defence Academy |
| Citations | 12 |
| Analysis | Full AI Review Included |
6CCVD Technical Documentation: Advanced Wide-Bandgap Semiconductor Analysis
Section titled â6CCVD Technical Documentation: Advanced Wide-Bandgap Semiconductor AnalysisâResearch Paper: Determination of Band Structure of Gallium-Arsenide and Aluminium-Arsenide Using Density Functional Theory
Executive Summary
Section titled âExecutive SummaryâThis research utilizes Density Functional Theory (DFT) to analyze the electronic structure and band gap characteristics of Gallium-Arsenide (GaAs) and Aluminium-Arsenide (AlAs). The findings underscore the continuous industry drive toward materials capable of operating efficiently under extreme conditions, validating the necessity for ultra-wide-bandgap solutions like MPCVD diamond.
- Semiconductor Characterization: The study successfully differentiated GaAs (Direct Band Gap, 0.37 eV calculated) and AlAs (Indirect Band Gap, 1.42 eV calculated) using the Local Density Approximation (LDA) within DFT.
- Application Relevance: GaAs is confirmed as suitable for optoelectronics devices (high electron transport), while AlAs is identified for high-temperature and strong electric fields device applications due to its wider band gap.
- Material Limitation: Both III-V semiconductors, while effective, possess fundamental band gaps significantly smaller than diamond (5.5 eV), limiting their performance ceiling in high-power density and extreme thermal environments.
- Computational Efficiency: The FHI-AIMS code demonstrated high accuracy in predicting band structure stability (using a 12x12x12 k-grid) within a short computational time (64.989 s).
- 6CCVD Value Proposition: For engineering applications demanding performance beyond the thermal and electrical limits of AlAs, 6CCVD provides Single Crystal Diamond (SCD) and Boron-Doped Diamond (BDD) materials, offering the widest band gap and highest thermal conductivity available.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| GaAs Calculated Band Gap (LDA) | 0.37 | eV | Direct Band Gap (Suitable for Optoelectronics) |
| AlAs Calculated Band Gap (LDA) | 1.42 | eV | Indirect Band Gap (Suitable for High T/Field) |
| GaAs Experimental Band Gap (Ref [1]/[2]) | 1.52 / 1.63 | eV | Observed values for reference comparison |
| AlAs Experimental Band Gap (Ref [1]/[2]) | 2.32 / 3.09 | eV | Observed values for reference comparison |
| Lattice Constant (Experimental) | 5.63 | Ă | Used for calculation of minimum total energy |
| Minimum Total Energy (GaAs/AlAs) | -114,915.7903 | eV | Calculated ground state energy |
| Computational Time (Minimum) | 64.989 | s | For required energy stability |
| SCF Convergence Accuracy (Ï) | 1E-5 | N/A | Charge density self-consistent field accuracy |
| SCF Convergence Accuracy (Etot) | 1E-6 | eV | Total energy self-consistent field accuracy |
| K-Grid Optimization | 12 x 12 x 12 | N/A | Optimized grid for energy stability |
| Calculated Band Width (GaAs) | 13.00 | eV | Large width indicates improved ionic nature |
| Calculated Band Width (AlAs) | 13.27 | eV | Large width indicates improved ionic nature |
Key Methodologies
Section titled âKey MethodologiesâThe electronic structure calculations for GaAs and AlAs were performed using the FHI-AIMS (Fritz Haber Institute Ab-initio Molecular Simulations) code, emphasizing efficient and accurate all-electron density-based calculations.
- Code and Environment: Calculations were carried out using FHI-AIMS code upgrade 6 on a Linux-based operating system (Ubuntu 14.04LTS), utilizing Intelâs FORTRAN 95 compiler (ifort) and necessary algebra subroutines (Lapack/BLAS).
- Theoretical Framework: The methodology employed Density Functional Theory (DFT) within the Local Density Approximation (LDA).
- Exchange-Correlation Functional: The Perdew-Wang (pw-lda) approximation was used for the exchange-correlation energy.
- Relativistic Treatment: A scalar relativistic treatment using the Atomic Zero-Order Regular Approximation (ZORA) was applied, ensuring robust treatment across elements.
- Geometry Input (
geometry.in):- The structure was specified in the diamond/zinc-blende configuration.
- Experimental lattice constant of 5.63 Ă was used to minimize the total energy.
- Atomic positions were defined using fractional coordinates (e.g., As at 0.25, 0.25, 0.25 and Ga at 0.00, 0.00, 0.00).
- SCF Convergence: Strict self-consistency convergence limits were set for charge density (
sc_accuracy_rho 1E-5), eigenvalues (sc_accuracy_eev 1E-3), and total energy (sc_accuracy_etot 1E-6), with an iteration limit of 100. - Band Structure Mapping: Electronic band structure was calculated along high-symmetry lines (L â Î â X â W â K) of the Brillouin zone using an optimized 12 x 12 x 12 k-grid.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe findings confirm that while III-V semiconductors like GaAs and AlAs are crucial for optoelectronics and moderate high-power applications, true next-generation high-temperature and high-field devices require an ultra-wide-bandgap material solution. MPCVD diamond supplied by 6CCVD is the definitive material choice, significantly exceeding the performance metrics of both GaAs and AlAs.
| Application Requirement | Research Context (GaAs/AlAs) | 6CCVD Diamond Solution | Technical Advantage (Diamond vs. AlAs) |
|---|---|---|---|
| High Electric Fields / High Temperature | AlAs (1.42 eV Band Gap) utilized for stability. | Optical Grade Single Crystal Diamond (SCD) | Band Gap: 5.5 eV (Ultimate thermal stability, superior voltage breakdown). |
| High Heat Dissipation | Thermal management is critical for device reliability. | Ultra-High Purity SCD Substrates | Thermal Conductivity: ~2000 W/m·K (vs. ~55 W/m·K for GaAs). Essential for high-density power electronics. |
| Optoelectronic Device Integration | Lasers, LEDs, Photo Detectors (requiring specific band energies). | SCD Substrates up to 500 ”m Thickness | Provides superior thermal sinking while maintaining optical transparency across UV/Visible/IR. |
| Conductive Layers / Electrodes | Designing for optimal electron transport properties. | Heavy Boron-Doped Diamond (BDD) | Customizable doping levels allow creation of conductive, highly stable electrodes or Ohmic contact layers on diamond surfaces. |
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research into next-generation high-power or extreme-environment devices, 6CCVD recommends the following materials, tailored to maximize the advantages of the 5.5 eV bandgap:
- Optical Grade Single Crystal Diamond (SCD): Required for high-purity, high-electric-field applications where thermal management and transparency are paramount. Available in thicknesses from 0.1 ”m to 500 ”m.
- Polycrystalline Diamond (PCD): Excellent thermal and mechanical properties for use as a highly stable heat spreader or substrate in large-area power modules (wafers up to 125mm).
- Boron-Doped Diamond (BDD): Essential for research requiring conductive layers (p-type semiconductor) stable under harsh chemical or thermal conditions, useful for creating integrated active components.
Customization Potential
Section titled âCustomization PotentialâThe integration of advanced III-V semiconductors like GaAs or AlAs onto diamond platforms often necessitates complex interfacing layers. 6CCVD provides full material customization to meet specific research parameters:
- Custom Dimensions and Shaping: We offer diamond plates and wafers up to 125mm (PCD) and provide precise laser cutting services to match specific component footprints or experimental jig requirements.
- Advanced Metalization Layers: We possess internal capability for depositing crucial metal contacts, including Au, Pt, Pd, Ti, W, and Cu, necessary for creating low-resistance Ohmic contacts or complex multilayer stacks (e.g., Ti/Pt/Au for bonding or gate interfaces).
- Polishing Standards: We ensure ultra-low surface roughness (Ra < 1nm for SCD, Ra < 5nm for Inch-size PCD) critical for high-quality epitaxy and device performance.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in the electronic and structural properties of wide-bandgap materials. We are prepared to assist engineering teams with material selection, interface design (e.g., metal/diamond contacts), and optimization for projects related to high-frequency electronic devices and extreme-environment optoelectronics, building upon the fundamental electronic structure analysis presented in this paper.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
This research paper is on Density Functional Theory (DFT) within Local Density Approximation. The calculation was performed using Fritz Haber Institute Ab-initio Molecular Simulations (FHIAIMS) code based on numerical atomic-centered orbital basis sets. The electronic band structure, total density of state (DOS) and band gap energy were calculated for Gallium-Arsenide and Aluminium-Arsenide in diamond structures. The result of minimum total energy and computational time obtained from the experimental lattice constant 5.63 A for both Gallium Arsenide and Aluminium Arsenide is -114,915.7903 eV and 64.989 s, respectively. The electronic band structure analysis shows that Aluminium-Arsenide is an indirect band gap semiconductor while Gallium-Arsenide is a direct band gap semiconductor. The energy gap results obtained for GaAs is 0.37 eV and AlAs is 1.42 eV. The band gap in GaAs observed is very small when compared to AlAs. This indicates that GaAs can exhibit high transport property of the electron in the semiconductor which makes it suitable for optoelectronics devices while the wider band gap of AlAs indicates their potentials can be used in high temperature and strong electric fields device applications. The results reveal a good agreement within reasonable acceptable errors when compared with the theoretical and experimental values obtained in the work of Federico and Yin wang [1] [2].