Etudiant : ZARROUK YOUSRA

Filière : Master Matériaux Avancés et Applications (M2A)

Encadrant : Pr. AMRI NABIL

Annèe : 2026

Résumé : This thesis investigates the electronic structure and Schottky barrier formation at the Pt(111)/ZnO(000-1) interface using density functional theory calculations. The work is motivated by the importance of metal–semiconductor contacts in ZnO-based electronic, optoelectronic and sensing devices, where the contact properties are controlled not only by the isolated metal and semiconductor, but also by the microscopic structure of the interface. The study first establishes the electronic properties of the separate materials. Standard PBEcalculations strongly underestimate the ZnO band gap, giving approximately 0.74 eV. To improve the ZnO electronic structure, a PBE+U approach was applied using effective Hubbard parameters of U(Zn) = 12 eV and U(O) = 5 eV. This correction shifts the Zn 3d states deeper into the valence region and increases the calculated band gap to approximately 3.38 eV, in close agreement with the experimental value. Bulk Pt is confirmed to be metallic, with Pt 5d states dominating the density of states near the Fermi level. The relaxed Pt/ZnO interface was then analyzed through the electrostatic potential, work function, projected density of states and layer-resolved electronic structure. The vacuum-referenced potential gives a slab work function of approximately 5.60 eV. Since the total density of states of the interface is metallic because of Pt, the ZnO band edges were extracted from the projected density of states of inner ZnO layers, where the direct perturbation from the metal is reduced. This procedure gives an electron Schottky barrier height of approximately 0.94 eV for the relaxed Pt(111)/O-terminated ZnO interface. Layer-resolved ZnO density of states reveals in-gap spectral weight close to the metal contact, decreasing toward the inner ZnO layers. This behavior is consistent with metal induced gap states and supports the use of inner ZnO layers as the reference region for barrier extraction. The results show that the Pt/ZnO Schottky barrier is governed by electrostatic alignment, Pt–ZnO coupling, interface dipole effects and interface-induced states.