Layered indium monoselenide (InSe) semiconductors have attracted extensive attention due to their promising applications in spectroscopy, thin-film electronics, and optoelectronic devices. The crystallographic polytypic nature of InSe facilitates diverse phase transitions, which, however, may compromise its exceptional performance under fluctuating environmental conditions. In this study, we synthesized high-quality β-InSe single crystals and systematically examined the evolution of phonon modes and polarization anisotropy over a temperature range of 80–400 K and under hydrostatic pressures up to 13.2 GPa using nondestructive Raman spectroscopy. The Raman spectra reveal two distinct out-of-plane A1(<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${\Gamma }_{1}^{2}$</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi mathvariant="normal">Γ</mi> <mrow> <mn>1</mn> </mrow> <mn>2</mn> </msubsup> </math></EquationSource> </InlineEquation>) and A1(<InlineEquation ID="IEq2"> <EquationSource Format="TEX">${\Gamma }_{1}^{3}$</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi mathvariant="normal">Γ</mi> <mrow> <mn>1</mn> </mrow> <mn>3</mn> </msubsup> </math></EquationSource> </InlineEquation>) modes, accompanied by an in-plane vibrational mode. The continuous Raman redshift observed upon heating is primarily attributed to intrinsic phonon–phonon anharmonicity, with cubic anharmonicity significantly dominating over quartic anharmonicity. Under hydrostatic pressure, consistent blueshifts were captured in all Raman-active phonon modes, driven by bond length contraction and increased vibrational energy. Notably, the applied pressure does not alter the material’s fourfold symmetry or polarization angles on the edge plane, owing to strong interlayer cohesion during slip. No spectral anomalies were detected within the investigated temperature and pressure ranges, highlighting the remarkable structural integrity of β-InSe. This research provides insights into the stable spectral performance of layered semiconductors, laying a foundation for their application in dynamic external environments.

Temperature, pressure, and angle-resolved polarization effects on Raman spectroscopy of layered β-InSe semiconductor single crystals

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发表日期：

2025年12月22日

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Hong Lu,
Zhigang Lai,
Rui Guo,
Jie Shu,
Penghao Sang,
Xiangjun Wang,
Wenqi Jiang,
Haotong Zang,
Wenjie Ji,
Xiao Ren

摘要

Layered indium monoselenide (InSe) semiconductors have attracted extensive attention due to their promising applications in spectroscopy, thin-film electronics, and optoelectronic devices. The crystallographic polytypic nature of InSe facilitates diverse phase transitions, which, however, may compromise its exceptional performance under fluctuating environmental conditions. In this study, we synthesized high-quality β-InSe single crystals and systematically examined the evolution of phonon modes and polarization anisotropy over a temperature range of 80–400 K and under hydrostatic pressures up to 13.2 GPa using nondestructive Raman spectroscopy. The Raman spectra reveal two distinct out-of-plane A₁( ${\Gamma }_{1}^{2}$ $Γ_{1}^{2}$ ) and A₁( ${\Gamma }_{1}^{3}$ $Γ_{1}^{3}$ ) modes, accompanied by an in-plane vibrational mode. The continuous Raman redshift observed upon heating is primarily attributed to intrinsic phonon–phonon anharmonicity, with cubic anharmonicity significantly dominating over quartic anharmonicity. Under hydrostatic pressure, consistent blueshifts were captured in all Raman-active phonon modes, driven by bond length contraction and increased vibrational energy. Notably, the applied pressure does not alter the material’s fourfold symmetry or polarization angles on the edge plane, owing to strong interlayer cohesion during slip. No spectral anomalies were detected within the investigated temperature and pressure ranges, highlighting the remarkable structural integrity of β-InSe. This research provides insights into the stable spectral performance of layered semiconductors, laying a foundation for their application in dynamic external environments.