Structural and electronic properties of nanoclusters (Xn, X = Au, Ag, Al; n = 1–4) adsorption on GaN/WS2 van der Waals heterojunction: A first principle study

Abstract

Metal decoration plays a critical role in the design of optoelectronic properties based on graphitic thin semiconductors. We propose a computational methodology that highlights the influences of meatal nanoclusters on the structural and electronic properties of single-layered GaN/WS2 vdW heterojunction. The energetic stability of Al clusters adhesion is demonstrated with positive dependence of cluster size. Obvious deformation is observed on GaN side after the deposition. The variation of work function is correlated with single/double dipole moment induced by charge transfer. A localized electric field parallel to surface is generated by Au adsorption, counter to a shallow portrait charge transfer of Ag. The charge density of models of Al clusters is redistributed, accompanied by a degradation of photovoltaic performance of the heterojunction. The GaN side exhibit a salient n-type conductivity after decoration, especially for cases of Al clusters. An impurity level is introduced within the bandgap and broadens as cluster size increases. This provides a handy tool to interpret band alignments and surface sensitization in graphitic semiconductors and buried interfaces.