Distinct ultrafast carrier dynamics of α-In(2)Se(3) and β-In(2)Se(3): contributions from band filling and bandgap renormalization.
Distinct ultrafast carrier dynamics of α-In(2)Se(3) and β-In(2)Se(3): contributions from band filling and bandgap renormalization.
复制标题
α-In2Se3 和 β-In2Se3 独特的超快载流子动力学：能带填充和带隙重整化的贡献
DOI：
10.1039/d1cp03874e
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发表时间：
2021
影响因子：
3.3
通讯作者：
Gao Bo
中科院分区：
文献类型：
--
作者：
Meng Shengjie;Wang Jian;Shi Hongyan;Sun Xiudong;Gao Bo
硒化铟（In_2Se_3）作为一种新型的层状二维半导体材料，因其优异的性能而受到广泛关注。迄今为止，对α-In 2Se 3和β-In 2Se 3的载流子动力学还缺乏全面的了解，这对于提高In 2Se 3基光电器件的性能至关重要。在本研究中，我们利用瞬态吸收显微镜研究了薄α-In 2Se 3和β-In 2Se 3中的超快载流子动力学。对于带隙较窄的α-In 2Se 3，带隙填充和带隙重整化共同决定了微分反射率信号的时间演化，其在不同延迟下的大小和符号由带隙填充和带隙重整化之间的权重决定，取决于载流子密度。对于带隙与探测光子能量接近的β-In 2Se 3，由于强的带填充效应，只能检测到正的微分反射率。在这两种材料中，寿命下降，俄歇过程的相对振幅增加，当泵浦能量密度增加。这些发现可以为In 2Se 3基器件的光学和光电特性提供进一步的见解。
As an intrigued layered 2D semiconductor material, indium selenide (In2Se3) has attracted widespread attention due to its excellent properties. So far, the carrier dynamics of α-In2Se3 and β-In2Se3 are still lacking a comprehensive understanding, which is essential to enhancing the performance of In2Se3-based optoelectronic devices. In this study, we explored the ultrafast carrier dynamics in thin α-In2Se3 and β-In2Se3via transient absorption microscopy. For α-In2Se3 with a narrower bandgap, band filling and bandgap renormalization jointly governed the time evolution of the differential reflectivity signal, whose magnitude and sign at different delays were determined by the weights between the band filling and bandgap renormalization, depending on the carrier density. For β-In2Se3, whose bandgap is close to the probe photon energy, only positive differential reflectivity was detected, which was attributed to strong band filling effect. In both materials, the lifetime decreased and the relative amplitude of the Auger process increased, when the pump fluence was increased. These findings could provide further insights into the optical and optoelectronic properties of In2Se3-based devices.