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Abstract 2D dilute magnetic semiconductors have been recently reported in transition metal dichalcogenides doped with spin‐polarized transition metal atoms, for example vanadium‐doped WS2monolayers, which exhibit room‐temperature ferromagnetic ordering. However, a broadband characterization of the electronic band structure of these doped WS2monolayers and its dependence on vanadium concentration is still lacking. Therefore, power‐dependent photoluminescence, resonant four‐wave mixing, and differential reflectance spectroscopies are performed here to study optical transitions close to the A exciton energy of vanadium‐doped WS2monolayers at three different doping levels. Instead of a single A exciton peak, vanadium‐doped samples exhibit two photoluminescence peaks associated with transitions from a donor‐like level and the conduction band minima. Moreover, resonant Raman and second‐harmonic generation experiments reveal a blueshift in the B exciton energy but no energy change in the C exciton after vanadium doping. Density functional theory calculations show that the band structure is sensitive to the HubbardUcorrection for vanadium, and several scenarios are proposed to explain the two photoluminescence peaks around the A exciton energy region. This work provides the first broadband optical characterization of these 2D dilute magnetic semiconductors, shedding light on the novel and tunable electronic features of V‐doped WS2 monolayers.
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Controllable p‐Type Doping of 2D WSe 2 via Vanadium Substitution
Abstract Scalable substitutional doping of 2D transition metal dichalcogenides is a prerequisite to developing next‐generation logic and memory devices based on 2D materials. To date, doping efforts are still nascent. Here, scalable growth and vanadium (V) doping of 2D WSe2at front‐end‐of‐line and back‐end‐of‐line compatible temperatures of 800 and 400 °C, respectively, is reported. A combination of experimental and theoretical studies confirm that vanadium atoms substitutionally replace tungsten in WSe2, which results inp‐type doping via the introduction of discrete defect levels that lie close to the valence band maxima. Thep‐type nature of the V dopants is further verified by constructed field‐effect transistors, where hole conduction becomes dominant with increasing vanadium concentration. Hence, this study presents a method to precisely control the density of intentionally introduced impurities, which is indispensable in the production of electronic‐grade wafer‐scale extrinsic 2D semiconductors.
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- PAR ID:
- 10450119
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 31
- Issue:
- 42
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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