arXiv subjects

Matinehsadat Hosseinigheidari

Publications and source records attributed to Matinehsadat Hosseinigheidari.

2 recordsLinked to original sources

arXiv2026

High-Field Electron Transport in AlGaN alloys: A Full-Band Monte Carlo Study Based on Ab Initio Supercell Calculations

AlGaN alloys are promising wide and ultra-wide-bandgap semiconductors for next-generation power and RF electronics applications. To realize the full potential of AlGaN based devices, it is important to understand the electron transport to accurately predict device performance and identify material limits under various operating conditions. In this work, the high-field electron transport properties of AlxGa1-xN are investigated using a supercell based full band Monte Carlo method. The supercell approach is employed to explicitly capture the true disorder of the alloy system, enabling a more realistic description of carrier transport. The velocity field characteristics are calculated across a range of Al compositions to evaluate key transport metrics, including peak velocity, saturation velocity, and critical electric field. The role of different scattering mechanisms is studied in detail to understand the high field transport mechanism in the AlGaN alloy system. In addition to steady state transport, transient electron dynamics are examined for various Al fractions to study velocity-overshoot behavior, which is especially important for improving the performance of scaled RF devices. Finally, the temperature dependence of the velocity field characteristics in ultra-wide-bandgap Al0.75Ga0.25N is investigated to assess its transport performance under high temperature conditions. These results provide a detailed understanding of high-field transport in AlGaN alloys and offer guidance for the design of AlGaN-based RF and power electronic devices.

cond-mat.mtrl-sci↗

arXiv2024

Effective Phonon Dispersion and Low field transport in AlxGa1-xN alloys using supercells: An ab-initio approach

To investigate the transport properties in random alloys, it is important to model the alloy disorder using supercells. Though traditional methods like Virtual Crystal Approximation (VCA) are computationally efficient, the local disorder in the system is not accurately captured as artificial translational symmetry is imposed on the system. However, in the case of supercells, the error introduced by self-image interaction between the impurities is reduced and translational symmetry is explicitly imposed over larger length scales. In this work, we have investigated the Effective Phonon Dispersion (EPD) and transport properties, from first principle calculations using supercells in AlxGa1-xN alloy systems. Using our in-house developed code, the EPD of AlGaN is obtained and the individual modes are identified. Next, we discuss our in-house developed method to calculate low-field transport properties in supercells. First to validate our methods we have solved the Boltzmann Transport Equation using Rode method to compare the phonon limited mobility in the 4 atom GaN primitive cell and 12 atom GaN supercell. Using the same technique, we have investigated the low field transport in random AlxGa1-xN alloy systems. Our calculations show that along with alloy scattering, electron-phonon scattering may also play an important role at room temperature and high-temperature device operation. This technique opens up the path for calculating phonon-limited transport properties in random alloy systems.

cond-mat.mtrl-sci↗