Fast detection of precipitates and oxides on CdZnTe surfaces by spectroscopic ellipsometry
Fast detection of precipitates and oxides on CdZnTe surfaces by spectroscopic ellipsometry
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DOI：
10.1007/s11664-007-0176-7
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发表时间：
2007-08-01
影响因子：
2.1
通讯作者：
Etcheberry, A.
中科院分区：
文献类型：
--
作者：
Badano, G.;Million, A.;Etcheberry, A.
用X射线光电子能谱和椭偏仪研究了Cd0.96Zn0.04Te(211)B的表面化学结构。在分子束外延生长非晶态Te和Cd薄膜后，首次用椭圆偏振法原位测量了Cd和Te在Cd0.96Zn0.04Te(211)B上的介电函数。然后我们研究了它们在空气中的氧化，发现Cd主要以氢氧化物的形式氧化，而Te则以TeO2的形式存在。在这两种情况下，薄膜的氧化都不是完全的，因为即使在几天的氧化之后，仍有大量的金属Te或Cd。随后，我们开发了一种基于Ce4+的化学腐蚀剂，以获得在空气中几乎不氧化的富Te的Cd0.96Zn0.04Te(211)B表面。另一种含有KCN的腐蚀剂大大减少了α-Te的量。最后，我们建立了Cd0.96Zn0.04Te(211)B表面非晶态Te丰度的初步光学模型。
We study the surface chemistry of Cd0.96Zn0.04Te(211)B by X-ray photoelectron spectroscopy and ellipsometry. We obtain first the dielectric functions of amorphous Te and Cd on Cd0.96Zn0.04Te(211)B by in situ ellipsometry after growing thin films of each material by molecular beam epitaxy. We then study their oxidation in air and show that Cd oxidizes primarily as a hydroxide whereas Te is present as TeO2. In neither case is the oxidation of the films complete, as a substantial amount of either metallic Te or Cd remains even after several days of oxidation. We subsequently exploit an electroless chemical etchant based on Ce4+, to produce Te-rich Cd0.96Zn0.04Te(211)B surfaces which oxidize very little in air. Another etchant containing KCN reduces the amount of alpha-Te substantially. Finally, we construct a tentative optical model for the Cd0.96Zn0.04Te(211)B surface that yields the abundance of amorphous Te on the surface.