Tuning Schottky Barrier and Contact Type of Metal–Semiconductor in Ti3C2T2/MoS2 (T = F, O, OH) by Strain: A First-Principles Study

Abstract

MXene is widely used for electrode materials. However, the interfacial resistance between metal and semiconductor affects the device performance. The strain has become an effective strategy to improve interfacial properties. With the aim of revealing the interface mechanism and improving device performance, we use the first-principles calculation to investigate the electronic properties of Ti3C2T2/MoS2 (T = F, O, OH) junctions and the effect of strain on the interfaces. The calculations show weak forces between Ti3C2T2 and MoS2 monolayer, and the interfacial interaction decreases in the order of Ti3C2(OH)2/MoS2, Ti3C2F2/MoS2, and Ti3C2O2/MoS2. Ti3C2F2/MoS2 exhibits a p-type Schottky barrier with 0.51 eV and Ti3C2O2/MoS2 shows a p-type Schottky barrier with 0.12 eV, whereas an n-type ohmic contact occurs in Ti3C2(OH)2/MoS2. Interestingly, the contact types and Schottky barrier height in the Ti3C2F2/MoS2 and Ti3C2O2/MoS2 junctions can be tuned by biaxial strain in plane, which shows a transition from a p-type Schottky contact to an n-type Schottky contact and then to an n-type ohmic contact. An ohmic contact is maintained in Ti3C2(OH)2/MoS2. Furthermore, the tunneling probability (TP) of Ti3C2(OH)2/MoS2 with 27.34% drops sharply, although the TP of Ti3C2F2/MoS2 and Ti3C2O2/MoS2 gradually increases with increasing strain. The controllable contact type and barrier in the Ti3C2T2/MoS2 junction make it a promising candidate for high-performance electronic devices.