Crystallization behavior and defect analysis on induction growth of hexagonal GaN in isothermal relaxation

Analysis of Anisotropic Growth and Defect Development of Hexagonal GaN under Atomic Simulation

“…In this study, the process of crystallization induced by crystals in different crystal orientations was simulated based on the large-scale atomic/molecular massively parallel simulator (LAMMPS) . The Stillinger–Weber (S-W) potential was used to describe the interatomic interactions, which has been widely used to study the properties of GaN. − The MD simulations were carried out under the NPT (constant atom number, system pressure, and temperature) ensemble with temperature and pressure controlled by a Nosé–Hoover thermostat and a constant pressure gauge, respectively, with the pressure set to 0 and the temperature set to 2800 K. This temperature was set because Jeffries et al reported that the crystal quality of GaN grown at high temperatures is superior to low temperatures, and our previous study also found that crystals with higher crystal quality are grown at 2800 K . A time step of 1 fs was used, and periodic boundary conditions were applied in the XYZ directions.…”

“…31 The Stillinger−Weber (S-W) potential 32 was used to describe the interatomic interactions, which has been widely used to study the properties of GaN. 33−37 The MD simulations were carried out under the NPT (constant atom number, system pressure, and temperature) ensemble 38 with temperature and pressure controlled by a Nose−Hoover thermostat and a constant pressure gauge, respectively, with the pressure set to 0 and the temperature set to 2800 K. This temperature was set because Jeffries et al reported that the crystal quality of GaN grown at high temperatures is superior to low temperatures, 39 and our previous study also found that crystals with higher crystal quality are grown at 2800 K. 30 A time step of 1 fs was used, and periodic boundary conditions were applied in the XYZ directions. Figure 1 shows a solid−liquid (S-L) model consisting of 24,000 atoms, where the solid part has the same number of atoms as well as volume as the liquid part, ensuring the spatial symmetry of the S-L model.…”

“…Molecular dynamics simulations have also been used to study the growth of GaN films on the (0001) wurtzite surface, and the N:Ga ratio was found to have an important effect on the crystallinity . A recent study has shown that the amorphous growth of GaN crystals induced by [0001] crystal orientation at high temperatures can lead to crystals with a polycrystalline structure . Most of the above studies on molecular dynamics simulations of GaN crystal growth have focused on the exploration of crystal growth techniques in a particular crystal orientation.…”

“…29 A recent study has shown that the amorphous growth of GaN crystals induced by [0001] crystal orientation at high temperatures can lead to crystals with a polycrystalline structure. 30 Most of the above studies on molecular dynamics simulations of GaN crystal growth have focused on the exploration of crystal growth techniques in a particular crystal orientation. However, the study of the GaN anisotropic growth mechanism can deepen the understanding of the nature of crystal properties.…”

Crystal Structure and Surface Morphology of GaN Thin Films Grown on Different Patterned AlN Substrate Surfaces

“…Interest in atomic layer deposition (ALD) technology is increasing due to the focus on microelectronics and deep submicron chip technology, which demand smaller device and material sizes. , The majority of GaN thin films deposited on sapphire or GaN substrates. − Nevertheless, the lattice mismatch exists between sapphire substrate and GaN. − To address this issue, aluminum nitride (AlN) has been widely used as a buffer layer to enhance the crystalline quality of GaN thin films. , Additionally, AlN films fabricated via the plasma-enhanced atom layer deposition (PEALD) process were utilized by Zhang et al as a passivation layer on the AlGaN/GaN surface . Therefore, it is crucial to investigate how different AlN buffer layer characteristics affect the formation of GaN thin films to improve the quality of the GaN thin films and increase the efficiency of LEDs made with GaN.…”