Modulating Electronic Structure of Monolayer Transition Metal Dichalcogenides by Substitutional Nb‐Doping

Abstract

Modulating electronic structure of monolayer transition metal dichalcogenides (TMDCs) is important for many applications and doping is an effective way towards this goal, yet is challenging to control. Here we report the in-situ substitutional doping of niobium (Nb) into TMDCs with tunable concentrations during chemical vapour deposition. Taking monolayer WS2 as an example, doping Nb into its lattice leads to bandgap changes in the range 1.98 eV to 1.65 eV. Noteworthy, 2 electrical transport measurements and density functional theory calculations show that the 4d electron orbitals of the Nb dopants contribute to the density of states of Nb-doped WS2 around the Fermi level, resulting in an n to p-type conversion. Nb-doping also reduces the energy barrier of hydrogen absorption in WS2, leading to an improved electrocatalytic hydrogen evolution performance. These results highlight the effectiveness of controlled doping in modulating the electronic structure of TMDCs and their use in electronic related applications.

Heterophase Boundary for Active Hydrogen Evolution in MoTe2

“…[ 41,42 ] The HER activity of the heterophase boundary can be further tuned by modulating the band bending via doping, strain, substitution, or electric gating. [ 35,36,43 ]…”

Doping Concentration Modulation in Vanadium-Doped Monolayer Molybdenum Disulfide for Synaptic Transistors

“…Doping concentration is important in the modification of the physical properties of 2D TMDCs. For example, Nb-doped MoS2 with a doping concentration of 2 at% shows an n-type transport behavior [16] while it turns to a p-type behavior when the doping concentration increases to 4.7 at% [17] . Therefore, many efforts have been devoted to modulate the doping concentrations of CVD-grown TMDCs by changing the additive amounts of doping precursors, but high-concentration doping of MoS2 remains a challenge.…”

Recent Advances on Transition Metal Dichalcogenides for Electrochemical Energy Conversion

“…In situ bottom‐up approaches based on hydrothermal/solvothermal/CVD growth are also efficient routes to realize the metal atom substitution in TMDCs lattice. [ 35,120,121 ] Bao and co‐workers have decorated the isolated Co atoms into the basal plane of mesoporous MoS 2 architecture (Figure 7i). [ 122 ] The hierarchical mesoporous structure accelerates the mass transport while the decorated Co atoms can improve the intrinsic HER activity of the in‐plane sulfur sites.…”