In:
Crystals, MDPI AG, Vol. 13, No. 2 ( 2023-02-13), p. 308-
Abstract:
In this work, we propose a method to prepare large-area, crystalline ultrathin rare-earth (RE, i.e., Eu, Yb, Er and Tb)-doped MoS2 thin films, using magnetron sputtering and subsequent Ar + H2 annealing. The film thickness of as-deposited samples varied from 60 to 100 nm, and decreases to be below 10 nm after annealing at 550 °C for 30 min. X-ray diffraction and Raman spectra analysis revealed that the sample films were crystallized after the annealing, which resulted in a MoS2 crystallite size of about 4–5 nm. X-ray photoelectron spectroscopy indicated that most of the RE ions existed in the films in trivalent states. The optical bandgap of the RE-doped MoS2 samples decreased from 1.6 eV (undoped) to 1.3 eV (Eu-doped) in the UV-vis absorption spectra. Electrical measurements showed that the electrical resistance decreased from 9.13 MΩ (undoped) to 0.34 MΩ (Yb-doped), the carrier density increased by one to two orders of magnitude and the carrier mobility decreased from 5.4 cm2/V·s (undoped) to 0.65 cm2/V·s (Yb-doped). The sign of the Hall coefficients indicated that the undoped MoS2 and the Yb-, Tb- and Er-doped MoS2 samples were n-type semiconductors, while the Eu-doped sample showed p-type characteristics. This study may be helpful to broaden the photoelectronic applications of these two-dimensional materials.
Type of Medium:
Online Resource
ISSN:
2073-4352
DOI:
10.3390/cryst13020308
Language:
English
Publisher:
MDPI AG
Publication Date:
2023
detail.hit.zdb_id:
2661516-2
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