Surface stoichiometry of pulsed ultraviolet laser treated polycrystalline CdTe
Surface stoichiometry of pulsed ultraviolet laser treated polycrystalline CdTe
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脉冲紫外激光处理多晶 CdTe 的表面化学计量
DOI：
10.1063/1.4887079
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发表时间：
2014
影响因子：
3.2
通讯作者：
M. Scarpulla
中科院分区：
文献类型：
--
作者：
B. Simonds;V. Palekis;B. Devener;C. Ferekides;M. Scarpulla
利用角分辨X射线光电子能谱（XPS）研究了纳秒脉冲紫外激光退火对近空间升华多晶薄膜表面化学计量比的影响。原始数据表明形成的富镉的表面层，但这是相反的期望的基础上的Cd和Te的蒸气压以上的CdTe，预测的富Te层和直接观察元素Te的表面。为了解释这一明显的差异，我们分析了我们的XPS数据的背景下，横向偏析的Cd和Te在表面上的脉冲激光处理后，与一个简单的模型的角度依赖XPS在表面粗糙度的存在下。这一分析表明，一个均匀的Te层不能解释我们的结果。相反，我们的分析表明，Te富集发生在晶界附近，亚单层镉层存在于其他地方。这些复杂但可重复的结果强调了测量表面化学计量的挑战。
The effects of nanosecond pulsed ultraviolet laser annealing on the surface stoichiometry of close-space sublimated polycrystalline thin films are investigated using angle-resolved x-ray photoemission spectroscopy (XPS). The raw data suggest the formation of a Cd-rich surface layer, but this is counter to the expectation based on Cd and Te vapor pressures above CdTe that predicts a Te-rich layer and to direct observation of elemental Te at the surface. In order to explain this apparent discrepancy, we analyze our XPS data in the context of prior reports of lateral segregation of Cd and Te at the surface after pulsed laser treatments with a simple model of angular dependent XPS in the presence of surface roughness. This analysis reveals that a uniform Te layer cannot explain our results. Instead, our analysis suggests that Te enrichment occurs near grain boundaries and that a sub-monolayer Cd layer exists elsewhere. These complex yet repeatable results underscore the challenges in measuring surface stoichi...