arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1012.3600cond-mat.mtrl-sciquant-ph
收藏

ZnO中的超快屏蔽和载流子动力学:理论与实验

Ultrafast screening and carrier dynamics in ZnO: Theory and experiment

Marijn A. M. Versteegh, Tim Kuis, H. T. C. Stoof, Jaap I. Dijkhuis

摘要:

当载流子密度高于莫特密度时,库仑屏蔽破坏了激子共振。这与带隙重整化和带填充一起严重影响了光谱。我们已经实验研究了这些影响的超快泵浦-探测反射率测量ZnO单晶在激子共振周围的各种波长,并在一个广泛的载流子密度范围。理论上我们确定了ZnO在300 K时的Mott密度为$1.5\times10^{24}$ m $^{-3}$。采用场论方法,我们推导并求解了Bethe-Salpeter阶梯方程,计算了密度相关的反射率和吸收光谱。建立了载流子动力学模型,包括三光子吸收、载流子冷却和表面附近的载流子俘获。基于我们模型的理论反射率与实验数据之间的一致性非常好。

英文摘要:

At carrier densities above the Mott density Coulomb screening destroys the exciton resonance. This, together with band-gap renormalization and band filling, severely affects the optical spectra. We have experimentally studied these effects by ultrafast pump-probe reflectivity measurements on a ZnO single crystal at various wavelengths around the exciton resonance and in a broad carrier-density range. Theoretically we determined the Mott density in ZnO to be $1.5\times10^{24}$ m$^{-3}$ at 300 K. Taking a field-theoretical approach, we derived and solved the Bethe-Salpeter ladder equation and we computed the density-dependent reflectivity and absorption spectra. A carrier dynamics model has been developed, containing three-photon absorption, carrier cooling, and carrier trapping near the surface. The agreement between the theoretical reflectivity based on our model and the experimental data is excellent.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑