Abstract:
This thesis investigates the structural, electronic, elastic, and thermodynamic properties of Indium Arsenide (InAs) using first-principle density functional theories (DFT). InAs, an III-V compound semiconductor with promising applications in electronics, optoelectronics, and nanotechnology, exhibits unique physical properties that make it an interesting subject for study. Leveraging computational methods rooted in quantum mechanics, this research provides a comprehensive understanding of InAs's material behavior at the atomic and electronic levels. In selecting suitable DFT software, we opted for open-source plane-wave DFT code Quantum ESPRESSO. The study begins with an exploration of InAs's structural properties, including its crystal structure, lattice parameters, and atomic arrangements. By optimizing the crystal structure through DFT calculations in GGA-PBE, insights into the stability and phase transitions of InAs under various conditions are gained. In order to improve calculation accuracy, the convergence test of total energy with regard to the kinetic energy cutoff, k-point, and lattice constant of InAs was carried out for the GGA-PBE approximation. Subsequently, the electronic properties of InAs are investigated, elucidating its band structure, density of states, and bandgap. The calculated bandgap value of InAs is overestimated. Furthermore, the elastic properties of InAs are analyzed from the elastic constants (C11, C12, C44), providing valuable information about its mechanical behavior and structural stability. The calculated elastic constants satisfy the Born-Huang stability criteria and indicates InAs is mechanically stable at ambient condition. Additionally, the temperature dependencies of vibrational energy, free energy, entropy and heat capacity of InAs were calculated within room temperature and all are fairly in good agreement with experimental values. In General, this thesis contributes to the advancement of materials science and technology by providing insights into the properties of InAs and paving the way for the development of innovative materials and devices with enhanced performance and functionali ty
