Fundamental Properties of III-Nitride Surfaces

Effect of Step Edges on Adsorption Behavior for GaN(0001) Surfaces during Metalorganic Vapor Phase Epitaxy: An Ab Initio Study

“…We consider various atomic configurations, as schematically shown in Figure . The models, barring the ideal vicinal GaN(0001) surface shown in Figure (a), are constructed on the basis of the electron counting (EC) rule and previously reported reconstructions on GaN(0001) surfaces under the MOVPE growth condition. ,,− In these models, terrace regions are constructed by multiplying the (2 × 2) periodicity satisfying the EC rule . The surfaces of periodic (2 × 9) vicinal slab models comprise two (2 × 4) terrace regions and two single layer steps.…”

“…From theoretical viewpoints, the adsorption and desorption behavior on III-nitride surfaces during epitaxial growth has been carried out, and characteristic features of adatom kinetics that depend on the growth condition such as temperature and pressure have been clarified. − More recently, we have examined the adsorption behavior of adatoms at step edges of the GaN(0001) surface during MBE growth on the basis of ab initio calculations. , Different from MBE growth, the growth condition of the carrier gas is crucial for the step-flow growth in MOVPE. Therefore, investigating the adsorption behavior at the step edges under the MOVPE condition is a challenging issue.…”

Structural Stability of Vicinal AlN(0001) and GaN(0001) Surfaces with Steps and Kinks under Metal–Organic Vapor-Phase Epitaxy Condition: A First-Principles Study

“…The atomic arrangements of these slab models are determined on the basis of the electron counting (EC) rule and previously reported reconstructions on the flat AlN(0001) and GaN(0001) surfaces under MOVPE growth condition. − For the flat AlN(0001) and GaN(0001) surfaces, previous DFT calculations considering the chemical potentials of constituent elements have revealed that the stability and reconstructions depend on the chemical potentials; i.e., the atomic arrangements of the surface depend on the growth condition such as temperature and pressure. For the flat AlN(0001) surface, the calculated surface formation energies as a function of Al chemical potential have revealed that the (2 × 2) reconstruction with hydrogen-terminated N atoms and NH 2 groups (N ad –H+Al–NH 2 ) takes the lowest formation energy under N-rich limit while the formation energy for the (2 × 2) reconstruction with hydrogen-terminated N atoms and Al–H bonds (N ad –H+Al–H) is the lowest under moderately N-rich condition.…”