Dual‐Additive Assisted Chemical Vapor Deposition for the Growth of Mn‐Doped 2D MoS₂ with Tunable Electronic Properties

Abstract

Doping of bulk silicon and III–V materials has paved the foundation of the current semiconductor industry. Controlled doping of 2D semiconductors, which can also be used to tune their bandgap and type of carrier thus changing their electronic, optical, and catalytic properties, remains challenging. Here the substitutional doping of nonlike element dopant (Mn) at the Mo sites of 2D MoS2 is reported to tune its electronic and catalytic properties. The key for the successful incorporation of Mn into the MoS2 lattice stems from the development of a new growth technology called dual‐additive chemical vapor deposition. First, the addition of a MnO2 additive to the MoS2 growth process reshapes the morphology and increases lateral size of Mn‐doped MoS2. Second, a NaCl additive helps in promoting the substitutional doping and increases the concentration of Mn dopant to 1.7 at%. Because Mn has more valance electrons than Mo, its doping into MoS2 shifts the Fermi level toward the conduction band, resulting in improved electrical contact in field effect transistors. Mn doping also increases the hydrogen evolution activity of MoS2 electrocatalysts. This work provides a growth method for doping nonlike elements into 2D MoS2 and potentially many other 2D materials to modify their properties.

Engineering 2D Materials: A Viable Pathway for Improved Electrochemical Energy Storage

“…Owing to the 2D structure and the structural support from the carbon cloth, the device also exhibited nearly identical current-voltage curve, with and without bending/twisting ( Figure 3e), and a high energy density of 69.1 Wh kg −1 at a power density of 0.985 kW kg −1 , along with an excellent cyclic stability ( Figure 3f). Similar doping effects were also confirmed by Cheng et al [122] In addition, the ultralong cyclic life (Figure 3e,f) demonstrated by Lee et al suggested that the stability of the 1T phase could be readily improved via appropriate chemical doping, which is highly critical in developing 1T TMCs for energy storage applications.…”

“…[106][107][108] Similar chemical doping (e.g., B, P, S, and F) was also investigated to enhance the power performance via improving the surface pseudocapacitance [109] and quantum capacitance, [110] regulating interface compatibility, [109] enlarging potential window and so on. [111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126] Like in the case of graphene, chemical doping of other 2D materials can also regulate the energy storage performance.…”

“…There are several ways that chemical doping could offer to contribute to the improvement in energy storage performance, including the pseudocapacitance (with new redox active center), boosted charge mobility and DOS at the Fermi level (e.g., charge charrier density, the C q in Equations (2) and (3), a new gap to give quantum capacitance ( C tot increased, Equation (2)), the increased interlayer spacing to improve ion accessibility and C dielec ( C tot increased, Equation (2)), the enhanced stability, and the newly formed charge injection to improve binding ability with ions (reducing the d in Equation (1)). [ 101–126 ] A quick instance is O functional groups on graphene's surface, which offer additional pseudocapacitance. Nevertheless, these O‐functionalized groups are generally unstable, reducing the charge mobility of graphene.…”

“…[ 106–108 ] Similar chemical doping (e.g., B, P, S, and F) was also investigated to enhance the power performance via improving the surface pseudocapacitance [ 109 ] and quantum capacitance, [ 110 ] regulating interface compatibility, [ 109 ] enlarging potential window and so on. [ 111–126 ]…”

Dissolution-precipitation growth of uniform and clean two dimensional transition metal dichalcogenides

“…This feature is reported in the literature using similar methods. [5,13,36,37] In sharp contrast in Figure 3b, the MoS2 flakes grown using the DP method exhibit a clean surface except for a protrusion under each flake which is the Mo precursor confirmed by the AFM images of transferred MoS2 in Figure 3c. Second, we exposed the surface of the substrate on which the MoS2 flakes had grown to TiCl4 vapor in humid air.…”