Transient charge carrier distribution at UV-photoexcited SiO2/Si interfaces
Transient charge carrier distribution at UV-photoexcited SiO2/Si interfaces
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DOI：
10.1103/physrevb.61.r5070
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发表时间：
2000-02-15
影响因子：
3.7
通讯作者：
Billardon, M
中科院分区：
文献类型：
--
作者：
Marsi, M;Belkhou, R;Billardon, M
我们用时间分辨泵浦-探测芯能级光电子能谱研究了紫外自由电子激光光激发后SiO2 /Si界面电荷分布的瞬态状态。我们发现，在Si衬底中产生的电子可以在氧化物层的表面处积累，强烈地影响界面处的电场。对于n型硅，这种效应可以导致带的曲率的增强，而不是由于表面光电压而导致的预期的平坦化。这种真空瞬态充电在氧化物层的表面上的特征衰减时间显着取决于其厚度，我们的研究结果表明，约12埃的氧化物厚度，它是可比的典型的过剩载流子复合时间在硅空间电荷层。
We used time-resolved pump-probe core level photoemission spectroscopy to study the transient regime of the charge distribution at SiO2 /Si interfaces after photoexcitation with an UV free electron laser. We found that electrons generated in the Si substrate can accumulate at the surface of the oxide layer, strongly affecting the electric field at the interface, For n-type silicon, this effect can lead to an enhancement of the curvature of the bands, rather than to the expected flattening due to surface photovoltage. The characteristic decay time of this vacuum transient charging at the surface of the oxide layer depends markedly on its thickness; our results indicate that for about 12-Angstrom oxide thickness, it is comparable to the typical excess carrier recombination time in silicon space charge layers.