Stability of Carbon Incorpoated Semipolar GaN(1101) Surface

Abstract

The structural stability of carbon incorporated GaN(1101) surfaces is theoretically investigated by performing first-principles pseudopotential calculations. The calculated surface formation energies taking account of the metal organic vapor phase epitaxy conditions demonstrate that several carbon incorporated surfaces are stabilized depending on the growth conditions. Using surface phase diagrams, which are obtained by comparing the calculated adsorption energy with vapor-phase chemical potentials, we find that the semipolar surface forms NH2 and CH2 below ∼1660 K while the polar GaN(0001) surface with CH3 is stabilized below ∼1550 K. This difference could be one of possible explanations for p-type doping on the semipolar GaN(1101) surface.