PROPRIETES STRUCTURALES ET ELECTRONIQUES DES HETEROSTRUCTURES BIDIMENSIONNELLES

Abstract

In this work, we investigated the structural and electronic properties of MXene/GaN hetero-structures, choosing TM2CX2 (TM = Ti, Hf and Zr) as representative MXenes. Using the pseudo-potential (PP) method based on the formalism of density functional theory (DFT). For the term of the exchange and correlation potential, we used the generalized gradient approximation (GGA). Our calculations reveal that the presence of GaN in these hétéro-structures decreases the band gap. On the other hand, the electronic band structures of TM2CO2 and monolayer GaN are almost preserved in the combined TM2CO2/GaN hetero-structure. . It is well known that simple DFT calculations based on local or semi-local exchange correlation functionals fail to describe the correct bandgap energy. For this reason, we used the non-local functional, hybrid Heyd−Scuseria−Ernzerhof (HSE). We confirm that the GGA underestimates the bandgap energy values. Our results indicate that these hetero-structures, due to their gap energy, can be useful in the thermoelectric field.