Electrical and optoelectronic anisotropy and surface electron accumulation in ReS2 nanostructures

Hemanth Kumar Bangolla; Muhammad Yusuf Fakhri; Ching Hsuan Lin; Cheng Maw Cheng; Yi Hung Lu; Tsu Yi Fu; Pushpa Selvarasu; Rajesh Kumar Ulaganathan; Raman Sankar; Ruei San Chen

doi:10.1039/d3nr04830f

Electrical and optoelectronic anisotropy and surface electron accumulation in ReS₂ nanostructures

Hemanth Kumar Bangolla, Muhammad Yusuf Fakhri, Ching Hsuan Lin, Cheng Maw Cheng, Yi Hung Lu, Tsu Yi Fu, Pushpa Selvarasu, Rajesh Kumar Ulaganathan, Raman Sankar, Ruei San Chen^*

^*Corresponding author for this work

Department of Physics

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS₂ nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS₂ nanoflakes. The presence of surface electron accumulation (SEA) in ReS₂ has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼10¹⁹ cm⁻³) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS₂ nanostructures.

Original language	English
Pages (from-to)	19735-19745
Number of pages	11
Journal	Nanoscale
Volume	15
Issue number	48
DOIs	https://doi.org/10.1039/d3nr04830f
Publication status	Published - 2023 Nov 15

ASJC Scopus subject areas

General Materials Science

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title = "Electrical and optoelectronic anisotropy and surface electron accumulation in ReS2 nanostructures",

abstract = "Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS2 nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS2 nanoflakes. The presence of surface electron accumulation (SEA) in ReS2 has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼1019 cm−3) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS2 nanostructures.",

author = "Bangolla, {Hemanth Kumar} and {Yusuf Fakhri}, Muhammad and Lin, {Ching Hsuan} and Cheng, {Cheng Maw} and Lu, {Yi Hung} and Fu, {Tsu Yi} and Pushpa Selvarasu and Ulaganathan, {Rajesh Kumar} and Raman Sankar and Chen, {Ruei San}",

note = "Publisher Copyright: {\textcopyright} 2023 The Royal Society of Chemistry.",

year = "2023",

month = nov,

day = "15",

doi = "10.1039/d3nr04830f",

language = "English",

volume = "15",

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T1 - Electrical and optoelectronic anisotropy and surface electron accumulation in ReS2 nanostructures

AU - Bangolla, Hemanth Kumar

AU - Yusuf Fakhri, Muhammad

AU - Lin, Ching Hsuan

AU - Cheng, Cheng Maw

AU - Lu, Yi Hung

AU - Fu, Tsu Yi

AU - Selvarasu, Pushpa

AU - Ulaganathan, Rajesh Kumar

AU - Sankar, Raman

AU - Chen, Ruei San

PY - 2023/11/15

Y1 - 2023/11/15

N2 - Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS2 nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS2 nanoflakes. The presence of surface electron accumulation (SEA) in ReS2 has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼1019 cm−3) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS2 nanostructures.

AB - Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS2 nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS2 nanoflakes. The presence of surface electron accumulation (SEA) in ReS2 has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼1019 cm−3) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS2 nanostructures.

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JO - Nanoscale

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Electrical and optoelectronic anisotropy and surface electron accumulation in ReS₂ nanostructures

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