<p>Raman spectroscopy with a 532 nm laser excitation was employed to investigate line intensity ratios and linewidths in mechanically exfoliated graphene in various configurations: single-layer graphene (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$G_{1L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>1</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>), double-layer graphene (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$G_{2L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>), multilayer graphene (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$G_{ML}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mi mathvariant="italic">ML</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>), and hBN-graphene heterostructures. The <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$I_{2D} / I_{G}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>I</mi> <mrow> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo stretchy="false">/</mo> <msub> <mi>I</mi> <mi>G</mi> </msub> </mrow> </math></EquationSource> </InlineEquation> peak ratio ranges from approximately 2.49−3.5 for <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$G_{1L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>1</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> with a full-width at half-maximum (FWHM) of 32 <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\mathrm{{cm^{-1}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi mathvariant="normal">cm</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation>, 0.75–1 for <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$G_{2L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>, and 0.42–0.54 for <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$G_{ML}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mi mathvariant="italic">ML</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>. In contrast, hBN/<InlineEquation ID="IEq9"> <EquationSource Format="TEX">$G_{1L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>1</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and hBN/<InlineEquation ID="IEq10"> <EquationSource Format="TEX">$G_{1L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mn>1</mn> <mi>L</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>/hBN heterostructures exhibited enhanced ratios of 6 and 10, respectively, with corresponding full-width at half-maximum values of 26 <InlineEquation ID="IEq11"> <EquationSource Format="TEX">$\mathrm{{cm^{-1}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi mathvariant="normal">cm</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> and 20.5 <InlineEquation ID="IEq12"> <EquationSource Format="TEX">$\mathrm{{cm^{-1}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi mathvariant="normal">cm</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation>, respectively. These results demonstrate that hBN encapsulation significantly improves the structural quality of graphene by reducing defect density.</p>

Raman Spectroscopy Study of Single Layer and Multilayer hBN/Graphene Heterostructures

期刊论文
发表日期：

2026年3月30日

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Prachanda Bhurtel,
Bidur Dahal,
Rameshwor Poudel,
W. D. Kisaru Upananda,
Eesha Razia,
Riya Sharma,
Dhammika Rathnayaka,
U. Kushan Wijewardena,
Annika Kriisa,
Rasanga Samaraweera,
Ramesh G. Mani

摘要

Raman spectroscopy with a 532 nm laser excitation was employed to investigate line intensity ratios and linewidths in mechanically exfoliated graphene in various configurations: single-layer graphene ( $G_{1L}$ $G_{1 L}$ ), double-layer graphene ( $G_{2L}$ $G_{2 L}$ ), multilayer graphene ( $G_{ML}$ $G_{ML}$ ), and hBN-graphene heterostructures. The $I_{2D} / I_{G}$ $I_{2 D} / I_{G}$ peak ratio ranges from approximately 2.49−3.5 for $G_{1L}$ $G_{1 L}$ with a full-width at half-maximum (FWHM) of 32 $\mathrm{{cm^{-1}}}$ ${cm}^{- 1}$ , 0.75–1 for $G_{2L}$ $G_{2 L}$ , and 0.42–0.54 for $G_{ML}$ $G_{ML}$ . In contrast, hBN/ $G_{1L}$ $G_{1 L}$ and hBN/ $G_{1L}$ $G_{1 L}$ /hBN heterostructures exhibited enhanced ratios of 6 and 10, respectively, with corresponding full-width at half-maximum values of 26 $\mathrm{{cm^{-1}}}$ ${cm}^{- 1}$ and 20.5 $\mathrm{{cm^{-1}}}$ ${cm}^{- 1}$ , respectively. These results demonstrate that hBN encapsulation significantly improves the structural quality of graphene by reducing defect density.