Raman Scattering and Exciton Photoluminescence in Few-Layer GaSe: Thickness- and Temperature-Dependent Behaviors,The Journal of Physical Chemistry C

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Raman Scattering and Exciton Photoluminescence in Few-Layer GaSe: Thickness- and Temperature-Dependent Behaviors
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2022-06-17 , DOI: 10.1021/acs.jpcc.2c02127
Muhammad Usman ₁ , Sergii Golovynskyi ₂ , Dan Dong ₂ , Yan Lin ₂ , Zhongyu Yue ₂ , Muhammad Imran ₃ , Baikui Li ₂ , Honglei Wu ₂ , Liang Wang ₁

Affiliation

The optical properties of few-layer (FL) GaSe are investigated using thickness- and temperature-dependent Raman scattering and photoluminescence (PL) spectroscopies. The vibrational modes exhibit linear softening with increasing temperature, with temperature coefficient values related to anharmonic phonon–phonon/electron coupling. Micro-PL is used to study the variation of exciton bands and structural features of FL GaSe. The temperature-dependent study from 100 to 380 K shows that the PL red-shifts due to a band gap narrowing, while the intensity decreases attributable to thermally stimulated nonradiative recombination caused by an increase in the electron–phonon interaction. The behavior of free and bound excitons and deep defect PL with temperature is studied by fitting the PL spectra with modeling equations. This enables the evaluation of their quenching activation energies and other significant aspects. The exciton binding energy of 0.3 eV has been calculated for the excitons in 10L GaSe. These novel findings extend the knowledge on the variety of exciton and deep defect levels in 2D GaSe and are important for its future applications in nano-optoelectronics involving external influence of optical properties.

中文翻译：

少层 GaSe 中的拉曼散射和激子光致发光：与厚度和温度有关的行为

使用依赖于厚度和温度的拉曼散射和光致发光 (PL) 光谱来研究少层 (FL) GaSe 的光学特性。随着温度的升高，振动模式表现出线性软化，温度系数值与非谐波声子-声子/电子耦合有关。Micro-PL 用于研究 FL GaSe 的激子带的变化和结构特征。从 100 到 380 K 的温度相关研究表明，由于带隙变窄，PL 红移，而强度降低是由于电子 - 声子相互作用增加引起的热刺激非辐射复合。通过用建模方程拟合 PL 光谱，研究了自由和束缚激子和深缺陷 PL 随温度的行为。这使得能够评估它们的猝灭活化能和其他重要方面。对于 10L GaSe 中的激子，计算了 0.3 eV 的激子结合能。这些新发现扩展了对 2D GaSe 中激子多样性和深缺陷能级的认识，并且对于其在涉及光学性质的外部影响的纳米光电子学中的未来应用非常重要。

更新日期：2022-06-17

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