Ultrafast dynamics of exciton formation in semiconductor nanowires.
Ultrafast dynamics of exciton formation in semiconductor nanowires.
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DOI：
10.1002/smll.201200156
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发表时间：
2012-06
期刊：
影响因子：
13.3
通讯作者：
C. Yong;H. Joyce;J. Lloyd‐Hughes;Q. Gao;H. Tan;C. Jagadish;M. Johnston;L. Herz
中科院分区：
文献类型：
--
作者：
C. Yong;H. Joyce;J. Lloyd‐Hughes;Q. Gao;H. Tan;C. Jagadish;M. Johnston;L. Herz
利用飞秒瞬态光致发光谱研究了GaAs-AlGaAs-GaAs核壳皮纳米线中自由电子空穴对和激子的动力学行为。在非共振激发后，观察到最初产生的电子-空穴等离子体到激子种群的双分子相互转换。这种从导电到绝缘的转变似乎在电子-空穴电荷对密度为2-4 × 10（16）cm（-3）时逐渐发生。莫特过渡的平滑性归因于自由电荷载流子到激子的双分子相互转换期间的缓慢载流子冷却以及导致不均匀光谱特性的化学势波动的存在。这些结果表明，高质量的纳米线是模型系统，用于研究一维异质结构中的基本科学效应。
The dynamics of free electron-hole pairs and excitons in GaAs-AlGaAs-GaAs core-shell-skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K. Following nonresonant excitation, a bimolecular interconversion of the initially generated electron-hole plasma into an exciton population is observed. This conducting-to-insulating transition appears to occur gradually over electron-hole charge pair densities of 2-4 × 10(16) cm(-3) . The smoothness of the Mott transition is attributed to the slow carrier-cooling during the bimolecular interconversion of free charge carriers into excitons and to the presence of chemical-potential fluctuations leading to inhomogeneous spectral characteristics. These results demonstrate that high-quality nanowires are model systems for investigating fundamental scientific effects in 1D heterostructures.