Using first-principles calculations based on density functional theory,we have systematically studied the influence of in-plane lattice constant and thickness of slabs on the concentration and distribution of two-dimensional hole gas (2DHG)in A1N/GaN supedattices.We show that the increase of in-plane lattice constant would increase the concentration of 2DHG at interfaces and decrease the valence band offset,which may lead to a leak of current.Increasing the thickness of A1N and/or decreasing the thickness of GaN would remarkably strengthen the internal field in GaN layer,resulting in better confinement of 2DHG at A1N/GaN interfaces.Therefore,a moderate larger in-plane lattice constant and thicker A1N layer could improve the concentration and confinement of 2DHG at A1N/GaN interfaces.Our study could serve as a guide to control the properties of 2DHG at Ⅲ-nitride interfaces and help to optimize the performance of p-type nitride-based devices.