Subpicosecond thermalization and relaxation of highly photoexcited electrons and holes in intrinsic and p-type GaAs and InP.
Subpicosecond thermalization and relaxation of highly photoexcited electrons and holes in intrinsic and p-type GaAs and InP.
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DOI：
10.1103/physrevb.47.13233
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发表时间：
1993-05
期刊：
影响因子：
--
通讯作者：
Hohenester;Supancic;Kocevar;Zhou;Kütt;Kurz
中科院分区：
文献类型：
--
作者：
Hohenester;Supancic;Kocevar;Zhou;Kütt;Kurz
对本征和 p 型体 GaAs 和 InP 中光激发电子和空穴的热化和弛豫进行了实验和理论相结合的研究。使用 50-fs 和 2-eV 激光激发脉冲，通过 2 eV 下的瞬态吸收变化和时间分辨率为 50\char21{}80 fs 的时间分辨发光光谱来研究热载流子动力学。选择材料和掺杂水平，结合广泛的系综蒙特卡罗模拟，获得有关电子和空穴的层间和带间转移、非平衡光学声子、电离载流子\char21{}中性受主散射以及各种载流子-载流子相互作用的动态筛选的影响的详细信息。对于瞬态吸收漂白和带隙发光作为时间和掺杂的函数，理论与实验之间存在非常好的一致性。对于超过 500 fs 的时间，根据测量的发光光谱定义的有效等离子体温度 ${\mathit{T}}_{\mathit{e}\mathit{f}\mathit{f}}$ 可以通过理论很好地再现。对于较短的时间，计算出的 ${\mathit{T}}_{\mathit{e}\mathit{f}\mathit{f}}$ 系统地过高。这种偏差暂时归因于碰撞展宽和能带非抛物线的影响。
A combined experimental and theoretical investigation of the thermalization and relaxation of optically excited electrons and holes in intrinsic and p-type bulk GaAs and InP is presented. Using 50-fs and 2-eV laser-excitation pulses the hot-carrier dynamics was studied by the transient-absorption changes at 2 eV and by time-resolved luminescence spectroscopy, with a time resolution of 50\char21{}80 fs. The materials and doping levels were chosen to obtain, in combination with extensive ensemble Monte Carlo simulations, detailed information on intervalley and interband transfers of electrons and holes and on the effects of nonequilibrium optic phonons, of ionizing carrier\char21{}neutral-acceptor scatterings, and of dynamical screening of the various carrier-carrier interactions. Very good agreement between theory and experiment is found for the transient-absorption bleachings and the band-gap luminescence as functions of time and doping. For times beyond 500 fs the effective plasma-temperatures ${\mathit{T}}_{\mathit{e}\mathit{f}\mathit{f}}$, defined from the measured luminescence spectra, are well reproduced by theory. For shorter times, the calculated ${\mathit{T}}_{\mathit{e}\mathit{f}\mathit{f}}$ are systematically too high. This deviation is tentatively ascribed to effects of collisional broadening and band nonparabolicities.