TY - JOUR
T1 - Anomalous photoluminescence thermal quenching of sandwiched single layer MoS_2
AU - Tangi, Malleswararao
AU - Shakfa, Mohammad Khaled
AU - Mishra, Pawan
AU - Li, Ming-yang
AU - Chiu, Ming-Hui
AU - Ng, Tien Khee
AU - Li, Lain-Jong
AU - Ooi, Boon S.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1614-01-01
Acknowledgements: King Abdulaziz City for Science and Technology (KACST); King Abdullah University of Science and Technology (KAUST) (KACST TIC R2-FP-008 and BAS/1/1614-01-01).
PY - 2017/9/22
Y1 - 2017/9/22
N2 - We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS2. For this study, MoS2 layers were chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N lattice matched templates. Later, to accomplish air-stable sandwiched SL-MoS2, a thin In0.15Al0.85N cap layer was deposited on the MoS2/In0.15Al0.85N heterostructure. We confirm that the sandwiched MoS2 is a single layer from optical and structural analyses using µ-Raman spectroscopy and scanning transmission electron microscopy, respectively. By using high-resolution X-ray photoelectron spectroscopy, no structural phase transition of MoS2 is noticed. The recombination processes of bound and free excitons were analyzed by the power-dependent µ-PL studies at 77 K and room temperature (RT). The temperature-dependent micro photoluminescence (TDPL) measurements were carried out in the temperature range of 77 – 400 K. As temperature increases, a significant red-shift is observed for the free-exciton PL peak, revealing the delocalization of carriers. Further, we observe unconventional negative thermal quenching behavior, the enhancement of the µ-PL intensity with increasing temperatures up to 300K, which is explained by carrier hopping transitions that take place between shallow localized states to the band-edges. Thus, this study renders a fundamental insight into understanding the anomalous thermal quenching of µ-PL intensity of sandwiched SL-MoS2.
AB - We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS2. For this study, MoS2 layers were chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N lattice matched templates. Later, to accomplish air-stable sandwiched SL-MoS2, a thin In0.15Al0.85N cap layer was deposited on the MoS2/In0.15Al0.85N heterostructure. We confirm that the sandwiched MoS2 is a single layer from optical and structural analyses using µ-Raman spectroscopy and scanning transmission electron microscopy, respectively. By using high-resolution X-ray photoelectron spectroscopy, no structural phase transition of MoS2 is noticed. The recombination processes of bound and free excitons were analyzed by the power-dependent µ-PL studies at 77 K and room temperature (RT). The temperature-dependent micro photoluminescence (TDPL) measurements were carried out in the temperature range of 77 – 400 K. As temperature increases, a significant red-shift is observed for the free-exciton PL peak, revealing the delocalization of carriers. Further, we observe unconventional negative thermal quenching behavior, the enhancement of the µ-PL intensity with increasing temperatures up to 300K, which is explained by carrier hopping transitions that take place between shallow localized states to the band-edges. Thus, this study renders a fundamental insight into understanding the anomalous thermal quenching of µ-PL intensity of sandwiched SL-MoS2.
UR - http://hdl.handle.net/10754/625508
UR - https://www.osapublishing.org/ome/abstract.cfm?uri=ome-7-10-3697
UR - http://www.scopus.com/inward/record.url?scp=85030170274&partnerID=8YFLogxK
U2 - 10.1364/OME.7.003697
DO - 10.1364/OME.7.003697
M3 - Article
SN - 2159-3930
VL - 7
SP - 3697
JO - Optical Materials Express
JF - Optical Materials Express
IS - 10
ER -