Interfacial Interaction between HfO2 and MoS2: From Thin Films to Monolayer

The interfacial interaction between high-κ dielectrics and two-dimensional channel materials plays an important role in determining electronic properties of high-performance electronic devices. In this study, via first-principles calculations, we show that the interaction between oxygen-terminated HfO2 (111) and the MoS2 monolayer is weak and dominated by the van der Waals force. This weak interaction results in symmetric band offsets which are larger than 1 eV. The presence of oxygen vacancies in HfO2 enhances the interfacial interaction significantly, leading to electron–hole puddles, larger effective masses, and localized midgap states in the MoS2. In contrast, strong interaction is found at the interface of hafnium-terminated HfO2 (111) and the MoS2 monolayer, but it results in inferior electronic properties. In addition, when the thickness of MoS2 increases, the formation of an oxygen-terminated HfO2 thin film on MoS2 becomes endothermic accompanied by asymmetrically increased band offsets due to red...