TY - JOUR

T1 - Integration of MoSe2Monolayers with Epitaxial High-k Gd2O3Substrate

T2 - Implication for High-Quality Emission and Modulation of Excitonic Quasiparticles

AU - Ghosh, Kritika

AU - Dhara, Avijit

AU - Dhara, Sajal

AU - Fissel, Andreas

AU - Osten, Hans Jörg

AU - Roy Chaudhuri, Ayan

N1 - Funding Information: ARC acknowledges SERB (CRG/2021/000811) and the Ministry of Human Resource Development, Govt of India (SPARC, vide letter No. SPARC/2018-2019/P252/SL); SD acknowledges SERB (CRG/2018/002845); IIT Kharagpur (special grant and ISIRD project grant) for partial financial support of the work. KG acknowledges a fellowship from DST-INSPIRE (IF180046). SD acknowledges the Ramanujan Fellowship research grant (SB/S2/RJN-110/2016), and ARC acknowledges a fellowship from the Alexander von Humboldt foundation. All authors acknowledge the Central Research Facility (CRF) of Indian Institute of Technology Kharagpur for various characterization facilities.

PY - 2022/7/22

Y1 - 2022/7/22

N2 - Monolayer (ML) transition-metal dichalcogenides (TMDCs) represent a novel class of materials for investigating excitonic quasiparticles in two dimensions and designing novel nanoscale optoelectronic devices. Practical application of the TMDC MLs requires their integration with appropriate substrates. In this context, dielectric substrates are of particular interest. Here, we report on the impact of an epitaxial high-Κ dielectric substrate on the excitonic quasiparticles in TMDC MLs. Investigations were performed by comparing the photoluminescence (PL) response of exfoliated MoSe 2MLs directly transferred onto an epitaxial Gd 2O 3layer grown on Si(001) and for comparison on the same Gd 2O 3layer covered with a few monolayers of hexagonal boron nitride (hBN) (hBN/Gd 2O 3). We demonstrate that in reference to hBN, the epitaxial Gd 2O 3substrate does not induce any significant biaxial strain to the MoSe 2MLs. Epitaxial Gd 2O 3led to a strong reduction in the inhomogeneous broadening of the emission peaks of MoSe 2MLs and only a marginal red shift in the A exciton and X -trion peak positions in comparison to the hBN/Gd 2O 3substrate. The PL response of MoSe 2MLs on epitaxial Gd 2O 3is dominated by X -trion resonance over a large range of temperatures, revealing strong charge transfer doping by the substrate. Our work illustrates the effect of the epitaxial high-κ dielectric substrate on the optical properties of MoSe 2monolayers and paves the way for realizing high-quality emission and modulation of excitonic quasiparticles through substrate engineering.

AB - Monolayer (ML) transition-metal dichalcogenides (TMDCs) represent a novel class of materials for investigating excitonic quasiparticles in two dimensions and designing novel nanoscale optoelectronic devices. Practical application of the TMDC MLs requires their integration with appropriate substrates. In this context, dielectric substrates are of particular interest. Here, we report on the impact of an epitaxial high-Κ dielectric substrate on the excitonic quasiparticles in TMDC MLs. Investigations were performed by comparing the photoluminescence (PL) response of exfoliated MoSe 2MLs directly transferred onto an epitaxial Gd 2O 3layer grown on Si(001) and for comparison on the same Gd 2O 3layer covered with a few monolayers of hexagonal boron nitride (hBN) (hBN/Gd 2O 3). We demonstrate that in reference to hBN, the epitaxial Gd 2O 3substrate does not induce any significant biaxial strain to the MoSe 2MLs. Epitaxial Gd 2O 3led to a strong reduction in the inhomogeneous broadening of the emission peaks of MoSe 2MLs and only a marginal red shift in the A exciton and X -trion peak positions in comparison to the hBN/Gd 2O 3substrate. The PL response of MoSe 2MLs on epitaxial Gd 2O 3is dominated by X -trion resonance over a large range of temperatures, revealing strong charge transfer doping by the substrate. Our work illustrates the effect of the epitaxial high-κ dielectric substrate on the optical properties of MoSe 2monolayers and paves the way for realizing high-quality emission and modulation of excitonic quasiparticles through substrate engineering.

KW - epitaxy

KW - gadolinium oxide

KW - high-κ dielectric

KW - molybdenum diselenide

KW - photoluminescence spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85134482410&partnerID=8YFLogxK

U2 - 10.1021/acsanm.2c01767

DO - 10.1021/acsanm.2c01767

M3 - Article

AN - SCOPUS:85134482410

VL - 5

SP - 9567

EP - 9575

JO - ACS Applied Nano Materials

JF - ACS Applied Nano Materials

IS - 7

ER -