Realization of N-Type Semiconducting of Phosphorene through Surface Metal Doping and Work Function Study

Abstract

Phosphorene becomes an important member of the layered nanomaterials since its discovery for the fabrication of nanodevices. In the experiments, pristine phosphorene shows -type semiconducting with no exception. To reach its full capability, -type semiconducting is a necessity. Here, we report the electronic structure engineering of phosphorene by surface metal atom doping. Five metal elements, Cu, Ag, Au, Li, and Na, have been considered which could form stable adsorption on phosphorene. These elements show patterns in their electron configuration with one valence electron in their outermost -orbital. Among three group 11 elements, Cu can induce -type degenerate semiconducting, while Ag and Au can only introduce localized impurity states. The distinct ability of Cu, compared to Ag and Au, is mainly attributed to the electronegativity. Cu has smaller electronegativity and thus denotes its electron to phosphorene, upshifting the Fermi level towards conduction band, resulting in -type semiconducting. Ag and Au have larger electronegativity and hardly transfer electrons to phosphorene. Parallel studies of Li and Na doping support these findings. In addition, Cu doping effectively regulates the work function of phosphorene, which gradually decreases upon increasing Cu concentration. It is also interesting that Au can hardly change the work function of phosphorene.

Data-Driven Discovery of Transition Metal Dichalcogenide-Based Z-Scheme Photocatalytic Heterostructures

“…The primary challenge lies in predicting the built-in electric field of a vdW 2D heterostructure before contact, including the magnitude and direction of charge transfer. Recent efforts have sought descriptors for charge transfer in vdW 2D heterostructures, including differences in work functions (Δ W ), covalent radii (Δ R ), and Pauling atomic electronegativities (Δχ) between two 2D materials. − However, these descriptors are either inapplicable or imprecise for distinguishing Z -scheme heterostructures from other categories, particularly from their type-II heterostructure parents as they share the same Δ W , Δ R , and Δχ.…”

Enhanced carrier transport by transition metal doping in WS2 field effect transistors

“…Owing to the unique nature of the vdW gaps, the atomic dopants in 2D materials can also intercalate between the layers, resulting in the changes in morphologic, electronic, optical, magnetic, and catalytic properties etc 19,20 . Compared to group XI elements such as Ag and Au which are widely used for wire-bonding, interconnects, and electrode materials, Cu as a representative transition metal has been demonstrated to effectively shift the Fermi level (EF) up to the minima of the conduction band edge (EC) and induce an n-type doping on black phosphorus (BP, or phosphorene), owing to its low electronegativity which can easily donate its 4s electron to BP 21,22 . The Cu doping effect on other 2D materials, such as graphene 23 , MoS2 24,25 , MoSe2 25 , Bi2Se3 [26][27][28] , ZrSe2 29 , SnSe2 30 , and SnS 31 etc.…”