Comparative ab initio study of the hole mobility in AlN and GaN
ORAL
Abstract
Group-III nitrides are semiconductors crucial for power electronics and optoelectronics. Among them, AlN is particularly promising due to its ultrawide bandgap, high breakdown field, and excellent thermal conductivity. In anticipation of the experimental realization of p-doped AlN, we report a state-of-the-art first-principles study of the hole mobility in AlN, and compare it with the more established GaN to elucidate their differences. We compute hole mobilities limited by phonons and ionized impurities using the ab initio Boltzmann transport equation, and include spin-orbit coupling, long-range dipole and quadrupole corrections, and GW quasiparticle bands. We find that the hole mobility in AlN reaches 178 cm2/Vs at room temperature along the c axis, which is one order of magnitude higher than the hole mobility of GaN. The higher mobility of AlN originates from its negative crystal-field splitting, which places the split-off holes at the top of the valence bands and far above the heavy holes.
*This research is supported by SUPREME, one of seven centers in JUMP 2.0, a Semiconductor Research Corporation (SRC) program sponsored by DARPA (calculations and analysis). This research is supported by the Computational Materials Science program of the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award DE-SC0020129. Computational resources were provided by the National Energy Research Scientific Computing Center (a DOE Office of Science User Facility supported under Contract No. DE-AC02-05CH11231), the Argonne Leadership Computing Facility (a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357), and the Texas Advanced Computing Center (TACC) at The University of Texas at Austin.
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Publication:High hole mobility in AlN from negative crystal-field splitting, submitted manuscript
