Interplay of Cu and oxygen vacancy in optical transitions and screening of excitons in ZnO:Cu films

被引：32

作者：

Darma, Yudi ^{[1
,2
,3
,4
]}

Herng, Tun Seng ^{[1
,5
]}

Marlina, Resti ^{[4
]}

Fauziah, Resti ^{[4
]}

Ding, Jun ^{[5
]}

Rusydi, Andrivo ^{[1
,2
,3
,4
]}

机构：

[1] Natl Univ Singapore, Singapore Synchrotron Light Source, Singapore 117603, Singapore

[2] Natl Univ Singapore, Dept Phys, Singapore 117542, Singapore

[3] Natl Univ Singapore, NUSNNI NanoCore, Singapore 117542, Singapore

[4] Inst Teknol Bandung, Dept Phys, Bandung 40132, Indonesia

[5] Natl Univ Singapore, Dept Mat Sci & Engn, Singapore 117574, Singapore

来源：

APPLIED PHYSICS LETTERS | 2014年 / 104卷 / 08期

基金：

新加坡国家研究基金会;

关键词：

CHEMICAL-VAPOR-DEPOSITION; THIN-FILMS; FERROMAGNETISM;

D O I：

10.1063/1.4866029

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We study room temperature optics and electronic structures of ZnO:Cu films as a function of Cu concentration using a combination of spectroscopic ellipsometry, photoluminescence, and ultraviolet-visible absorption spectroscopy. Mid-gap optical states, interband transitions, and excitons are observed and distinguishable. We argue that the mid-gap states are originated from interactions of Cu and oxygen vacancy (Vo). They are located below conduction band (Zn4s) and above valence band (O2p) promoting strong green emission and narrowing optical band gap. Excitonic states are screened and its intensities decrease upon Cu doping. Our results show the importance of Cu and Vo driving the electronic structures and optical transitions in ZnO: Cu films. (C) 2014 AIP Publishing LLC.

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