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control of nano-insulating film/metal interfaces for investigation of the origin of interface potential

控制纳米绝缘膜/金属界面以研究界面电位的起源

基本信息

批准号：
17560027
负责人：
MICHIKO Yoshitake
金额：
$ 2.18万
依托单位：
National Institute for Materials Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17560027/
关键词：
interface potential work function interface termination band alignment electronic devices materials for electrodes

项目摘要

Band alignment via interface termination control based on thermodynamicsThe interface potential and band alignment between epitaxial alumina and metal substrate were investigated using Cu and Ni single crystals with Al addition.From the previous experiments, it is known that the interface is terminated by, oxygen (O-term) when the interface was made by depositing Cu (111) and Ni (111) on alpha alumina According to the ab-initio calculations, thermodynamically stable interface expected to be aluminum terminated when Al is mixed with Cu or Ni. It reported that the kind of atoms at the interface is dependent on the activity of Al in the substrate. Based on this calculation, the interface between alumina and Cu-Al alloy (111)and NiAl (110) was made by carefully exposing the substrate to 1024L oxygen in ultra high vacuum under the partial oxygen pressure of 5×10^8 Torr at optimized temperature. The binding energy of Al 2p and valence band spectra were obtained in-situ during the growth of epitaxial alumina. The interface potential and band alignment were quantified by interpreting these spectral results.We confirmed that the interface is Al terminated when Al is added to Cu or Ni, as suggested from ab-initio calculations. Regarding the interface potential, band alignment at the interface, the band offset, energy difference between the valence band maximum of alumina and the Fermi level of the substrates were relatively large in our experimental results. This result agreed well with the prediction given by the first-principles calculation.In conclusion, we clarified that the interface potential is governed by the kind of atoms at the interfaces. Based on this, we were successful in modifying the band offset value by adding Al to metals far the changing the kind of interface terminating atoms from oxygen to aluminum. This method is based on thermodynamics and can be applied not only for metal-alumina interfaces but also for many systems of interests.

基于界面终止控制的能带对准研究了添加Al的Cu和Ni单晶外延Al 2 O3与金属衬底之间的界面电位和能带对准，从以前的实验中得知，界面终止是由，当通过在α氧化铝上沉积Cu（111）和Ni（111）形成界面时的氧（O-项）根据从头计算，当Al与Cu或Ni混合时，预期热稳定界面为铝端。据报道，界面原子的种类取决于基底中Al的活性。在此基础上，通过将Al 2 O3与Cu-Al合金（111）和NiAl（110）在最佳温度下在氧分压为5× 10^8Torr的超高真空中暴露于1024 L的氧气中，制备了Al 2 O3与Cu-Al合金（111）和NiAl（110）之间的界面。在外延生长过程中，原位测量了Al 2 p的结合能和价带谱。通过对光谱结果的解释，对界面势和能带排列进行了定量分析，证实了从头计算结果，当Al加入到Cu或Ni中时，界面是Al终止的。在我们的实验结果中，界面势、界面处的能带排列、能带偏移、Al 2 O3的价带顶与衬底费米能级之间的能量差都比较大。这一结果与第一性原理计算的结果吻合较好，说明界面势的大小与界面原子的种类有关。在此基础上，我们成功地通过向金属中添加Al来修改能带偏移值，从而将界面终止原子的种类从氧改变为铝。该方法是基于热力学的，不仅可以应用于金属-氧化铝界面，而且可以应用于许多感兴趣的系统。