A recent modelling study of the surface reconstruction after the NH3 pulse in ALD of AlN, GaN and InN, suggests that, at typical ALD temperatures and pressures, the AlN surface is predominantly covered by -NH2 species at thermal equilibrium. The surface chemistry of TMA and NH3 in ALD of AlN was also recently mapped out using density functional theory (DFT) , suggesting that the decomposition pathways of TMA are crucial for determining film growth rates. Three distinct decomposition pathways for TMA molecules on the surface were observed: