Intense Quantum Confinement Effects in Cu2O Thin Films

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• 作者：Panagiotis Poulopoulos ; Sotirios Baskoutas ; Spiridon D. Pappas ; Christos S. Garoufalis ; Sotirios A. Droulias ; Atieh Zamani ; Vassilios Kapaklis
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：August 4, 2011
• 年：2011
• 卷：115
• 期：30
• 页码：14839-14843
• 全文大小：777K
• 年卷期：v.115,no.30(August 4, 2011)
• ISSN：1932-7455

文摘

Thin Cu₂O films in the thickness range 0.75鈥?30 nm have been prepared on high-quality corning glass, quartz, and Si(100) substrates by radio frequency magnetron sputtering of Cu targets and subsequent oxidation in a furnace under air. Ultraviolet鈥搗isible light absorption spectroscopy experiments reveal a blue shift of the energy between the top valence and the first excited conduction sub-bands. The shift increases smoothly as the film thickness decreases. The maximum value observed for the thinnest film is very large, reaching a value of 1.2 eV. Such a shift was not easy to be observed in the past due to the very small Bohr radius of Cu₂O. The experimental results, which indicate the presence of intense quantum confinement effects, are well-described by theoretical calculations based on the potential morphing method in the Hartree鈥揊ock approximation.