Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride

Transition metal dichalcogenides (TMDs) materials possess intriguing optical and electrical properties, such as the formation of valley-polarised excitons and trions, offering potential for exciting applications in spintronics, valleytronics and optoelectronics. In this paper, we investigate the via...

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Main Author: Yeo, Think-E
Other Authors: Gao Weibo
Format: Final Year Project (FYP)
Language:English
Published: Nanyang Technological University 2024
Subjects:
Online Access:https://hdl.handle.net/10356/175691
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author Yeo, Think-E
author2 Gao Weibo
author_facet Gao Weibo
Yeo, Think-E
author_sort Yeo, Think-E
collection NTU
description Transition metal dichalcogenides (TMDs) materials possess intriguing optical and electrical properties, such as the formation of valley-polarised excitons and trions, offering potential for exciting applications in spintronics, valleytronics and optoelectronics. In this paper, we investigate the viability of doping TMDs, using ruthenium(III) chloride as an electron acceptor, via spontaneous charge transfer doping to study the properties of trions in TMDs. We characterized the trion response in TMD devices using reflection spectroscopy, observing the spectrum to verify whether charge transfer doping had occurred. The presence of trion resonance indicated that spontaneous charge transfer had indeed taken place. We then use electrical gating to determine the doping density in the TMDs due to the spontaneous charge transfer. Our findings revealed that hole doping in TMDs led to the formation of trions under photoexcitation, as evident from the trion response detected in the reflection contrast spectroscopy performed on molybdenum diselenide (MoSe2). However, no trion response was detected in tungsten diselenide (WSe2), contrary to theoretical predictions. This discrepancy could be attributed to inconsistencies in the layers of hBN spacer used, defects or contaminants introduced during device fabrication, or effects of lattice alignment. This study contributes to understanding doping mechanisms and trion behavior in TMDs. Further investigation into the factors influencing trion formation in different TMD materials could lead to improved control and utilization of their unique properties for future electronic and optoelectronic applications.
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spelling ntu-10356/1756912024-05-06T15:37:38Z Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride Yeo, Think-E Gao Weibo School of Physical and Mathematical Sciences wbgao@ntu.edu.sg Physics Transition metal dichalcogenides Spontaneous charge transfer doping Transition metal dichalcogenides (TMDs) materials possess intriguing optical and electrical properties, such as the formation of valley-polarised excitons and trions, offering potential for exciting applications in spintronics, valleytronics and optoelectronics. In this paper, we investigate the viability of doping TMDs, using ruthenium(III) chloride as an electron acceptor, via spontaneous charge transfer doping to study the properties of trions in TMDs. We characterized the trion response in TMD devices using reflection spectroscopy, observing the spectrum to verify whether charge transfer doping had occurred. The presence of trion resonance indicated that spontaneous charge transfer had indeed taken place. We then use electrical gating to determine the doping density in the TMDs due to the spontaneous charge transfer. Our findings revealed that hole doping in TMDs led to the formation of trions under photoexcitation, as evident from the trion response detected in the reflection contrast spectroscopy performed on molybdenum diselenide (MoSe2). However, no trion response was detected in tungsten diselenide (WSe2), contrary to theoretical predictions. This discrepancy could be attributed to inconsistencies in the layers of hBN spacer used, defects or contaminants introduced during device fabrication, or effects of lattice alignment. This study contributes to understanding doping mechanisms and trion behavior in TMDs. Further investigation into the factors influencing trion formation in different TMD materials could lead to improved control and utilization of their unique properties for future electronic and optoelectronic applications. Bachelor's degree 2024-05-03T04:27:29Z 2024-05-03T04:27:29Z 2024 Final Year Project (FYP) Yeo, T. (2024). Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/175691 https://hdl.handle.net/10356/175691 en application/pdf Nanyang Technological University
spellingShingle Physics
Transition metal dichalcogenides
Spontaneous charge transfer doping
Yeo, Think-E
Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title_full Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title_fullStr Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title_full_unstemmed Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title_short Spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium(III) chloride
title_sort spontaneous charge transfer doping of transition metal dichalcogenides via ruthenium iii chloride
topic Physics
Transition metal dichalcogenides
Spontaneous charge transfer doping
url https://hdl.handle.net/10356/175691
work_keys_str_mv AT yeothinke spontaneouschargetransferdopingoftransitionmetaldichalcogenidesviarutheniumiiichloride