Tuning the Electronic and Photonic Properties of Monolayer MoS₂ via In Situ Rhenium Substitutional Doping

Abstract

Doping is a fundamental requirement for tuning and improving the properties of conventional semiconductors. Recent doping studies including niobium (Nb) doping of molybdenum disulfide (MoS 2 ) and tungsten (W) doping of molybdenum diselenide (MoSe 2 ) have suggested that substitutional doping may provide an efficient route to tune the doping type and suppress deep trap levels of two dimensional (2D) materials. To date, the impact of the doping on the structural, electronic and photonic properties of in-situ doped monolayers remains unanswered due to challenges This article is protected by copyright. All rights reserved.2 including strong film-substrate charge transfer, and difficulty achieving doping concentrations greater than 0.3 at%. Here, we demonstrate in-situ rhenium (Re) doping of synthetic monolayer MoS 2 with ~1 at% Re. To limit substrate-film charge transfer r-plane sapphire is used. Electronic measurements demonstrate that 1 at% Re doping achieves nearly degenerate n-type doping, which agrees with density functional theory calculations. Moreover, low-temperature photoluminescence (PL) indicates a significant quench of the defect-bound emission when Re is introduced, which is attributed to the Mo-O bond and sulfur vacancies passivation and reduction in gap states due to the presence of Re.The work presented here demonstrates that Re doping of MoS 2 is a promising route towards electronic and photonic engineering of 2D materials.

Enabling room temperature ferromagnetism in monolayer MoS2 via in situ iron-doping

“…By contrast, the Fe:MoS 2 monolayer exhibits about the same intensities for the defect-induced emission and the A exciton, suggesting that Fe:MoS 2 monolayers possess a lower native point defect density 29 , and thus a lower sulfur vacancy concentration. Previous studies show that transition metal doping of MoSe 2 and MoS 2 can suppress the Se or S vacancies 19,30 . The reduced sulfur vacancies in Fe:MoS 2 monolayers can be caused by the Fe doping, which is evident from the Mo 3d electron peak in the XPS spectra ( Supplementary Fig.…”

“…Notably, first-principles studies predict that doping of transition metal ions into TMD monolayers is a promising way to realize a DMS with a T C at or above RT 15,16 . Although being constrained by solubility and chemical stability, transition metal elements can be doped to some extent into monolayer TMDs, but ferromagnetism was not demonstrated [17][18][19] . Nevertheless, enhanced doping concentration of 2% Mn in Mn: MoS 2 monolayers grown on a graphene substrate 17 and 1% rhenium (Re) in Re:MoS 2 monolayer exhibited suppression of defect-bound emission at low temperatures, demonstrating the feasibility of realizing in situ doping of TMD monolayers 20,21 .…”

A roadmap for electronic grade 2D materials

“…3 Most significantly, substrates can induce significant charge exchange across the 2D/substrate interface that substantially modulates PL emission (Figure 5d), 176,177 carrier lifetime, 2 field effect mobility, 178 and substitutional doping efficiency of 2D materials. 179,180 Furthermore, substrates with high dielectric constants similar to HfO2 can screen the columbic potential interacting with charged impurities, resulting in field effect mobility values of greater than 100 cm 2 /Vs for MoS2. 181 Beyond these basic properties, substrates also serve as key components in the realization of interesting physical phenomena, such as room-temperature plasmonic resonance in MoS2 on SiO2/Si nanodisk arrays.…”

Emerging nanofabrication and quantum confinement techniques for 2D materials beyond graphene

“…Doping of 2D materials can also be used as an atomic modification tool for tuning the optical, electronic, and structural properties and often arises from defect introduction. In general, the techniques reported include in situ substitutional doping 88,89 as well as ex situ doping. Here we will focus on ex situ doping, as it enables nanopatterning of defects within the lattice.…”