First-principles study of metal-semiconductor contact OF CS and X2CO2 (X=Ti, Zr, Hf) monolayers

Using first principles calculations, we have investigated the structural and electronic properties of Carbon Sulfide (CS) and X2CO2 (X=Ti, Zr, Hf) MXenes monolayers and their CS-X2CO2 (X=Ti, Zr, Hf) metal-semiconductor (MS) contacts. The energetic stability of MS contacts is confirmed by minimum binding energy. The intrinsic electronic properties of CS-X2CO2 are well preserved due to weak van der Waals (vdWs) contact. An indirect band gap semiconductor behavior is found for Ti2CO2, Zr2CO2, Hf2CO2, while CS and all MS contacts are metals. Our results show that the interface CS-X2CO2 formed p-type Schottky contact with a SBH of 0.69 eV. Furthermore, we also compute the electrostatic potential for CS-X2CO2 MS contacts, where the CS layer have deeper potential than X2CO2 layer and the electrons/charges of CS-X2CO2 MS contacts transfer from CS layer to X2CO2 monolayer. Also, we calculate the work function of CS-X2CO2 (X=Ti, Zr, Hf) MS contacts, which corresponds to minimum amount of energy required to remove an electron from the metal. These results will be useful for promising applications in field-effect transistors (FET) and photodetectors devices.