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Fe‐Doped p‐ZnO Nanostructures/n‐GaN Heterojunction for “Blue‐Free” Orange Light‐Emitting Diodes
Author(s) -
Zhao Wanqiu,
Xiong Xing,
Han Yibo,
Wen Li,
Zou Zhengguang,
Luo Shijun,
Li Haixia,
Su Jun,
Zhai Tianyou,
Gao Yihua
Publication year - 2017
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201700146
Subject(s) - materials science , doping , electroluminescence , photoluminescence , optoelectronics , cathodoluminescence , heterojunction , acceptor , nanowire , light emitting diode , diode , band gap , nanostructure , nanotechnology , layer (electronics) , luminescence , condensed matter physics , physics
In order to obtain the necessary band gap for light‐emitting diodes (LEDs) with zero emission at blue wavelengths (“blue‐free”), quasi‐3D nanostructures of p‐type Fe‐doped zinc oxide (ZnO:Fe) are fabricated on an n‐type GaN substrate. The ZnO:Fe nanostructure comprises an array of vertical nanowires attached at the nodes of a 2D network. Elemental analysis and field‐effect‐transistor (FET) and current–voltage ( I – V ) measurements indicate the successful iron‐doping of ZnO. After doping, the ZnO exhibits p‐type conductivity, a local‐charge‐reservoir layer, and an abundance of Fe‐related deep levels. The cathodoluminescence (CL), photoluminescence (PL) at various temperatures (down to 4.65 K), and electroluminescence (EL) confirm the creation of Fe‐related donor and acceptor levels. New donor levels may be attributed to the substitution of Fe for some Zn sites (“Fe Zn ”), while new acceptor levels may be due to the bind of Fe Zn with Zn vacancies, (producing Fe Zn – V Zn pairs). These doping‐induced energy levels are helpful in restricting the intrinsic ZnO UV and blue emission, and a stable blue‐free orange LED device is achieved. It has chromaticity coordinates of ∼(0.483, 0.447) and a color temperature of ∼2574 K under bias voltages of 6–16 V, making it potentially applicable to electronic display systems.