Hydrogen and magnesium incorporation on c-plane and m-plane GaN surfaces

Abstract

We present first-principles calculations for m-plane and c-plane In0.25Ga0.75N surfaces, focusing on how the growth conditions affect indium incorporation. For both surfaces the calculations indicate that In incorporation is energetically favorable provided the surface is wetted by In adlayers rather than passivated by hydrogen and NH2 groups. Growth of an In0.25Ga0.75N alloy therefore requires that the chemical potential of hydrogen be kept low. For growth at 700 C the partial pressure of H2 should be less than ~0.004 atm. for the m-plane and ~0.04 atm. for growth on the c-plane.