Lisanne Peters
Trinity College Dublin, AMBER Centre & CRANN, Graduate Student
Research Interests:
Non‐covalent functionalization of layered 2D materials is an essential tool to modify and fully harness their optical, electrical, and chemical properties. Herein, a facile method enabling the selective formation of self‐assembled... more
Non‐covalent functionalization of layered 2D materials is an essential tool to modify and fully harness their optical, electrical, and chemical properties. Herein, a facile method enabling the selective formation of self‐assembled monolayers (SAMs) of perylene bisimide (PBI) on transition metal dichalcogenides (TMDs), directly on the growth substrate (on‐chip), is presented. Laterally‐resolved infrared atomic force microscopy (AFM‐IR) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) are applied as superior techniques to gain detailed information beyond traditional surface analysis techniques, such as Raman spectroscopy and AFM, on TMD/PBI structures. The highly selective functionalization conducted in organic solution on MoS2 and WSe2 opens up a pathway to controllable, versatile functionalization of layered materials, which is highly sought after for its potential in passivation, tuning of properties and applications in optics, electronics, and (bio‐) sensing.
Research Interests:
Research Interests:
Rabi splitting occurs when the exchange of energy between an exciton and plasmon is quicker than their intrinsic dissipation rates. When these conditions are met, the energy of the system splits into two entirely new eigenstates above and... more
Rabi splitting occurs when the exchange of energy between an exciton and plasmon is quicker than their intrinsic dissipation rates. When these conditions are met, the energy of the system splits into two entirely new eigenstates above and below the energy of the original plasmon and exciton. These new energy peaks are called polaritons.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Atomic force microscopy (AFM) and scanning probe lithography can be used for the mechanical treatment of various surfaces, including polymers, metals, and semiconductors. The technique of nanoshaving, in which materials are removed using... more
Atomic force microscopy (AFM) and scanning probe lithography can be used for the mechanical treatment of various surfaces, including polymers, metals, and semiconductors. The technique of nanoshaving, in which materials are removed using the AFM tip, is employed in this work to produce nanopatterns of self-assembled monolayers (SAMs) on two-dimensional (2D) materials. The materials used are monolayers of transition metal dichalcogenides (TMDs), namely, MoS 2 and WS 2 , which are noncovalently functionalized with perylene diimide (PDI), a perylene derivative. The approach involves rastering an AFM probe across the surface at a controlled increased load in ambient conditions. As a result of the strong bond between PDI SAM and TMD, loads in excess of 1 μN are required to pattern the monolayer. Various predefined patterns, including a grating pattern with feature sizes below 250 nm, are demonstrated. Results indicate the high precision of nanoshaving as an accurate and nondestructive li...
Research Interests:
Research Interests:
Transition metal dichalcogenides (TMDs) have been a core constituent of 2D material research throughout the last decade. Over this time, research focus has progressively shifted from synthesis and fundamental investigations, to exploring... more
Transition metal dichalcogenides (TMDs) have been a core constituent of 2D material research throughout the last decade. Over this time, research focus has progressively shifted from synthesis and fundamental investigations, to exploring their properties for applied research such as electrochemical applications and integration in electrical devices. Due to the rapid pace of development, priority is often given to application-oriented aspects while careful characterisation and analysis of the TMD materials themselves is occasionally neglected. This can be particularly evident for characterisations involving X-ray photoelectron spectroscopy (XPS), where measurement, peak-fitting, and analysis can be complex and nuanced endeavours requiring specific expertise. To improve the availability and accessibility of reference information, here we present a detailed peak-fitted XPS analysis of ten transition metal chalcogenides. The materials were synthesised as large-area thin-films on SiO2 us...
Research Interests:
Research Interests:
Strong coupling was detected between single gold nano-bipyramids and mono-layer MoS2. It was demonstrated that the coupling strength increases with nanoparticle size, even without increasing the number of excitons coupled into the system.
Tungsten ditelluride is a layered transition metal dichalcogenide (TMD) that has attracted increasing research interest in recent years. WTe2 has demonstrated large non-saturating magnetoresistance, potential for spintronic applications... more
Tungsten ditelluride is a layered transition metal dichalcogenide (TMD) that has attracted increasing research interest in recent years. WTe2 has demonstrated large non-saturating magnetoresistance, potential for spintronic applications and promise as a type-II Weyl semimetal. The majority of works on WTe2 have relied on mechanically-exfoliated flakes from chemical vapour transport (CVT) grown crystals for their investigations. While producing high-quality samples, this method is hindered by several disadvantages including long synthesis times, high-temperature anneals and an inherent lack of scalability. In this work, a synthesis method is demonstrated that allows the production of large-area polycrystalline films of WTe2. This is achieved by the reaction of pre-deposited films of W and Te at a relatively low temperature of 550 degC. Sputter X-ray photoelectron spectroscopy reveals the rapid but self-limiting nature of the oxidation of these WTe2 films in ambient conditions. The WT...
Research Interests:
Rabi splitting occurs when the exchange of energy between an exciton and plasmon is quicker than their intrinsic dissipation rates. When these conditions are met, the energy of the system splits into two entirely new eigenstates above and... more
Rabi splitting occurs when the exchange of energy between an exciton and plasmon is quicker than their intrinsic dissipation rates. When these conditions are met, the energy of the system splits into two entirely new eigenstates above and below the energy of the original plasmon and exciton. These new energy peaks are called polaritons.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
We demonstrate a back-gate modulated field-emission current from a WSe2 monolayer and propose a new field-emission vertical transistor concept.
Research Interests:
The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments,... more
The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments, these steps remain very challenging, and transfer variations often result in unreliable 2D material properties. Here, it is demonstrated that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene. It is understood that interfacial water is essential for an electrochemistry-based graphene delamination from a Pt surface. Additionally, the lamination of graphene to a target wafer is hindered by intercalation effects, which can even result in graphene delamination from the target wafer. For circumvention of these issues, a direct, support-free graphene transfer process is demonstrated, which relies on the formation of interfacial water between graphene and its growth surface, while avoiding wate...
Research Interests:
We study the effect of polymer coating, pressure, temperature and light on the electrical characteristics of monolayer WSe2 back-gated transistors with quasi-ohmic Ni/Au contacts. We prove that the removal of a layer of poly(methyl... more
We study the effect of polymer coating, pressure, temperature and light on the electrical characteristics of monolayer WSe2 back-gated transistors with quasi-ohmic Ni/Au contacts. We prove that the removal of a layer of poly(methyl methacrylate) or a decrease of the pressure change the device conductivity from p to n-type. We demonstrate a gate-tunable Schottky barrier at the contacts and measure a barrier height of ~70 meV in flat-band condition. We report and discuss a temperature-driven change in the mobility and the subthreshold slope which we use to estimate the trap density at the WSe2/SiO2 interface. We study the spectral photoresponse of the device, that can be used as a photodetector with a responsivity of ~0.5 AW-1 at 700 nm wavelength and 0.37 mW/cm2 optical power.