Te-rich CdTe surface by pulsed UV laser treatment for ohmic back contact formation
Te-rich CdTe surface by pulsed UV laser treatment for ohmic back contact formation
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通过脉冲紫外激光处理富碲 CdTe 表面以形成欧姆背接触
DOI：
10.1109/pvsc.2014.6925413
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Scarpulla
中科院分区：
文献类型：
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作者：
B. Simonds;V. Palekis;B. V. Van Devener;C. Ferekides;M. Scarpulla
脉冲紫外激光治疗最近被应用于多晶碲化镉太阳能电池，以产生欧姆背接触。在这项工作中，我们利用x射线光电子能谱（XPS）研究了脉冲激光激发产生的表面化学计量变化。这些结果揭示了cd含量越来越高的表面，这与计算和其他人测量的结果相反。为了理解这种明显的分歧，我们建立了一个考虑表面形貌和表面相分离的样品表面的几何模型。由此，我们推断激光处理确实产生了预期的Te富集，但这种富集仅限于晶界附近。此外，由于地形和表面灵敏度效应以及在薄膜表面其他地方发现的亚单层Cd，富te区对XPS强度的贡献减少了，从而发生了明显的Cd富集。
Pulsed UV laser treatments have recently been applied to polycrystalline CdTe solar cells to create an ohmic back contact. In this work, we investigate the surface stoichiometry variations produced by pulsed laser excitation using X-ray photoelectron spectroscopy (XPS). These results reveal surfaces that are becoming more Cd-rich, counter to what is expected from calculations and what has been measured by others. To understand this apparent disagreement, we have constructed a geometric model of the sample surface considering surface topography and a segregation of phases at the surface. From this, we infer that the laser treatments do produce a Te enrichment as expected, but that this enrichment is localized near the grain boundaries. Furthermore, the apparent Cd-enrichment occurs because the Te-rich region's contribution to the XPS intensity is lessened by topographic and surface sensitivity effects as well as a sub-monolayer of Cd found elsewhere on the film surface.