Doping is a fundamental requirement for tuning and improving the properties of conventional semiconductors. Recent doping studies including niobium (Nb) doping of molybdenum disulfide (MoS2) and tungsten (W) doping of molybdenum diselenide (MoSe2) have suggested that substitutional doping may provide an efficient route to tune the doping type and suppress deep trap levels of 2D materials. To date, the impact of the doping on the structural, electronic, and photonic properties of in situ‐doped monolayers remains unanswered due to challenges including strong film substrate charge transfer, and difficulty achieving doping concentrations greater than 0.3 at%. Here, in situ rhenium (Re) doping of synthetic monolayer MoS2with ≈1 at% Re is demonstrated. To limit substrate film charge transfer,
Single-layer MoS2is a direct-gap semiconductor whose band edges character is dominated by the d-orbitals of the Mo atoms. It follows that substitutional doping of the Mo atoms has a significant impact on the material’s electronic properties, namely the size of the band gap and the position of the Fermi level. Here, density functional theory is used along with the G0W0method to examine the effects of substituting Mo with four different transition metal dopants: Nb, Tc, Ta, and Re. Nb and Ta possess one less valence electron than Mo does and are therefore p-type dopants, while Re and Tc are n-type dopants, having one more valence electron than Mo has. Four types of substitutional structures are considered for each dopant species: isolated atoms, lines, three-atom clusters centered on a S atom (c3s), and three-atom clusters centered on a hole (c3h). The c3h structure is found to be the most stable configuration for all dopant species. However, electronic structure calculations reveal that isolated dopants are preferable for efficient n- or p-type performance. Lastly, it is shown that photoluminescence measurements can provide valuable insight into the atomic structure of the doped material. Understanding these properties of substitutionally-doped MoS2can allow for its successful implementation into cutting-edge solid state devices.
more » « less- NSF-PAR ID:
- 10303246
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Nano Express
- Volume:
- 1
- Issue:
- 1
- ISSN:
- 2632-959X
- Page Range / eLocation ID:
- Article No. 010008
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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$${}_{{{{{{{{\rm{S}}}}}}}}}^{-1}$$ $${}_{{{{{{{{\rm{Mo}}}}}}}}}^{0}$$ $${}_{{{{{{{{\rm{Mo}}}}}}}}}^{-1}$$
