A5002755566- 2D Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- MXene and MAX Phase Materials
- Quantum Dots Synthesis And Properties
- Graphene research and applications
- Radiation Effects in Electronics
- Electrocatalysts for Energy Conversion
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- Semiconductor materials and devices
- Advanced Memory and Neural Computing
- Advanced Photocatalysis Techniques
- Ferroelectric and Negative Capacitance Devices
Trinity College Dublin
2017-2020
Advanced Materials and BioEngineering Research
2017
Precise and scalable defect engineering of 2D nanomaterials is acutely sought-after in contemporary materials science. Here we present monolayer graphene molybdenum disulfide (MoS$_2$) by irradiation with noble gas ions at 30 keV. Two ion species different masses were used a field source microscope: helium (He$^+$) neon (Ne$^+$). A detailed study the introduced sizes resulting inter-defect distance escalating dose was performed using Raman spectroscopy. Expanding on existing models, found...
We report on 2H-2H′/1T phase conversion of MoS2 and MoSe2 polycrystalline films grown by thermally assisted conversion. The structural the transition metal dichalcogenides was successfully carried out organolithium treatment chip. As a result we obtained new cophase system TMDs thin which verified Raman spectroscopy, X-ray diffraction, photoelectron spectroscopy. selected areas yielding lateral heterostructure between pristine 2H 2H′/1T regions. Scanning electron microscopy atomic force...
Wafer-scale fabrication of PtSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> MOSFETs was demonstrated by photolithography on Pt films directly selenized at 400 °C. Taking advantage the unique property to transition from a semiconductor semimetal as its thickness increases beyond few monolayers, channel recess adapted for improving gate control while keeping contact resistance below 0.01 Ω · cm. The wafer-scale resulted in uniform...
Molybdenum ditelluride (MoTe2) is a transition metal dichalcogenide (TMD) which has two phases stable under ambient conditions, semiconducting (2H) and semimetallic (1T′) phase. Despite host of interesting properties potential applications, MoTe2 one the less-studied TMDs, perhaps due its relatively low abundance in nature or challenges associated with synthesis, such as toxicity most precursors. In this report, we describe fabrication thin films phase-pure 1T′ using predeposited molybdenum...
The synthesis of transition metal dichalcogenides (TMDs) has been a primary focus for 2D nanomaterial research over the last 10 years, however, only small fraction this concentrated on ditellurides. In particular, nanoscale platinum ditelluride (PtTe2) rarely investigated, despite its potential applications in catalysis, photonics and spintronics. Of reports published, majority examine mechanically-exfoliated flakes from chemical vapor transport (CVT) grown crystals. This method produces...
The spectral dependence of nonradiative energy transfer (NRET) from three spectrally different quantum dot (QD) ensembles to monolayer MoS2 is reported. QDs with peak emission wavelengths 450, 530, and 630 nm induce large photocurrent enhancements in the hybrid devices islands grown by chemical vapor deposition (CVD). NRET efficiencies over 90% are observed for each QD-MoS2 hybrids, 3-fold 6-fold enhancements, depending on overlap between MoS2. We find good agreement trends obtained rate...
This report details the controllable doping of graphene through post‐growth plasma treatments. Defects are controllably introduced into lattice using argon plasma, following this sample exposed to ammonia/hydrogen plasma. During nitrogen atoms get incorporated causing partial restoration lattice. The damage levels characterised by Raman and X‐ray photoelectron spectroscopies. incorporation provides significant n‐doping. is confirmed fabrication field‐effect transistors which show clear...
We investigate the effects of lattice disorders on low frequency Raman spectra bilayer MoS2. The MoS2 was subjected to defect engineering by irradiation with a 30 keV He+ ion beam, and induced morphology change characterized transmission electron microscopy. When increasing dose, shear mode is observed red-shift, it also suppressed sharply compared other peaks. use linear chain model describe changes spectra. Our observations suggest that crystallite size orientation are dominant factors behind
The energy transfer mechanism leading to highly efficient nonradiative (NRET) from quantum dots (QDs) monolayer MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> devices has been investigated via a spectral dependence study. of the NRET three spectrally separated QD ensembles reveals that trends in rates follow overlap between emission and absorption spectra, thus verifying for is Förster-type NRET. Furthermore, photocurrent...
Tungsten ditelluride is a layered transition metal dichalcogenide (TMD) that has attracted increasing research interest in recent years. WTe2 demonstrated large non-saturating magnetoresistance, potential for spintronic applications and promise as type-II Weyl semimetal. The majority of works on have relied mechanically-exfoliated flakes from chemical vapour transport (CVT) grown crystals their investigations. While producing high-quality samples, this method hindered by several...