Strong Valence Electrons Dependent and Logical Relations of Elemental Impurities in 2D Binary Semiconductor: a Case...

Using first-principle calculations within density functional theory, we investigate the electronic property and stability of substitutionally doped 2D GeP₃ monolayer with dopants from group III to VI. The conducting properties are found to be dramatically modified by both the doping sites and the number of valence electrons of dopants. Specifically, substitution on Ge site exhibits metal-semiconductor oscillations as a function of the number of valence electrons of dopants, while such oscillations are totally reversed when substitution on P site. Moreover, we also study the case of co-doping in GeP₃, showing that co-doping can produce a logical "AND" phenomenon, that is, the conducting properties of co-doped GeP₃ can be deduced via a simple logical relation according to the results of single doping. Finally, we investigate the formation energy of dopants and find that the electron-hole and hole-hole co-doped systems are much more energetically favorable due to the Coulomb attraction. Our findings not only present a comprehensive understanding of 2D doping phenomenon, but also propose an intriguing route to tune the electronic properties of 2D binary semiconductors.