TY - JOUR
T1 - Ultrathin Rare-Earth-Doped MoS2 Crystalline Films Prepared with Magnetron Sputtering and Ar + H2 Post-Annealing
AU - Heng, Chenglin
AU - Wang, Xuan
AU - Zhao, Chaonan
AU - Wu, Gang
AU - Lv, Yanhui
AU - Wu, Hanchun
AU - Zhao, Ming
AU - Finstad, Terje G.
N1 - Publisher Copyright:
© 2023 by the authors.
PY - 2023/2
Y1 - 2023/2
N2 - 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.
AB - 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.
KW - MoS films
KW - magnetron sputtering
KW - photoelectrical property
KW - rare-earth doping
UR - http://www.scopus.com/inward/record.url?scp=85149226680&partnerID=8YFLogxK
U2 - 10.3390/cryst13020308
DO - 10.3390/cryst13020308
M3 - Article
AN - SCOPUS:85149226680
SN - 2073-4352
VL - 13
JO - Crystals
JF - Crystals
IS - 2
M1 - 308
ER -