Open AccessElectroluminescence from light-emitting devices based on erbium-doped ZnO/n-Si heterostructures: Enhancement effect of fluorine co-doping
Author(s) -
Jinxin Chen,
WenZhang Zhu,
Yuhan Gao,
Deren Yang,
Xiangyang Ma
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.030919
Subject(s) - materials science , electroluminescence , optoelectronics , doping , substrate (aquarium) , erbium , ion , heterojunction , light emitting diode , wafer , crystal (programming language) , semiconductor , nanotechnology , layer (electronics) , oceanography , geology , computer science , programming language , physics , quantum mechanics
We report on erbium (Er) related electroluminescence (EL) in the visible and near infrared (NIR) regions from the light-emitting device (LED) based on the Er-doped ZnO (ZnO:Er)/n-Si isotype heterostructure formed by sputtering ZnO:Er film on n-Si/n + -Si epitaxial wafer. Herein, the ZnO:Er film exhibits n-type in electrical conduction. The aforementioned LED is electroluminescent only under sufficiently high forward bias with the negative voltage connecting to n + -Si substrate. Such forward bias enables the electrons from n-Si to enter into the ultra-thin SiO x (x ≤ 2) layer inherently existing between the ZnO:Er film and n-Si via Poole-Frenkel conduction mechanism and, subsequently, to drift into the ZnO:Er film thus becoming hot electrons, which impact-excite the Er 3+ ions to emit characteristic visible and NIR light. Furthermore, the Er-related EL from the aforementioned LED can be significantly enhanced through adopting the strategy of co-doping F - ions into the ZnO host, which brings about twofold primary effects. Firstly, due to the atomic size compensation between F - and Er 3+ ions, the ZnO crystal grains become larger to accommodate much more optically active Er 3+ ions. Secondly, the partial substitution of F - ions for O 2- ions around the Er 3+ ion reduces the symmetry of pseudo-octahedral crystal field of Er 3+ ion, thus increasing the probabilities of intra-4f transitions of Er 3+ ions. We believe that this work sheds light on developing efficient silicon-based LEDs using the Er-doped oxide semiconductors.