Enhanced UV emission of Y-doped ZnO nanoparticles

doi:10.1016/j.apsusc.2012.03.010

Applied Surface Science

Volume 258, Issue 18, 1 July 2012, Pages 6735-6738

https://doi.org/10.1016/j.apsusc.2012.03.010 Get rights and content

Abstract

Y-doped ZnO (Zn_1−xY_xO) nanoparticles with different Y concentrations were synthesized by sol–gel method. The effects of Y concentration on the optical properties of the as-synthesized Zn_1−xY_xO nanoparticles were investigated. Photoluminescence (PL) measurements revealed that doping of Y in ZnO induced an evidence increase of UV emission. At Y concentration x = 0.07, the UV emission intensity reached maximum, which is about 9 times higher than that of the compared pure ZnO nanoparticles. Exceeding this concentration, the formation of Y₂O₃ causes a decrease in the UV emission intensity. This enhanced UV emission enables Zn_1−xY_xO system potential applications in supersensitive UV detector sinimaging, photosensing, and intrachip optical interconnects.

Highlights

► Rare earth element Y was doped in ZnO nanoparticles and the saturation concentration of Y in ZnO lattice is 6.12 at%. ► The UV emission of ZnO can be significantly increased by Y doping in ZnO lattice. ► The deep level emission of ZnO was suppressed by Y doping and a high intensity ratio (32) of UV to DLE was obtained.

Introduction

Rare-earth (RE) doped semiconductors have been the focus of numerous investigations because of their unique optical properties and promising applications in optoelectronic devices [1], [2], [3], [4], [5]. As one of the most important II–VI semiconductors with wide band gap, ZnO is an environmentally friendly and chemically stable material and is a suitable host material for the doping of metal and RE ions because of its outstanding photoluminescence (PL) properties [6], [7], [8]. RE-doped ZnO nanocrystals are expected to be potential candidate materials for flat panel displays due to enhanced emission in visible light range [9], [10], [11]. Ce-doped ZnO [12] showed red shift and Er-doped ZnO thin films [13] showed blue shift in their photoluminescence spectra. The UV luminescence of ZnO was quenched by Eu-doping and a strong visible emission around 618 nm was observed [14].

It is well known that UV emission in photoluminescence is the main character of ZnO and an intensive UV emission is desirable. However, until now, few experimental studies have focused on the enhance intensity of UV by doping RE or metallic ions into ZnO lattice. In this paper, Y-doped ZnO nanoparticles were prepared via sol–gel method and the effect of Y concentration on the photoluminescence properties was investigated.

Section snippets

Experimental

Zn_1−xY_xO powders with x = 0.00, 0.03, 0.05, 0.07 and 0.09 at% were prepared via sol–gel method. All the chemical reagents used in the experiment were analytical grade purity. Zinc nitrate [Zn(NO₃)₂·6H₂O] at 0.1 M concentration and different ratios of yttrium nitrate at 0.1 M [Y(NO₃)₂·3H₂O] were dissolved into 0.3 M citrate acid [C₆H₈O₇·H₂O] solution with stirring to form sol. Then, the mixture was polymerized to form gel at 80 °C for 12 h. The swelled gel was pyrolyzed at 130 °C for 5 h to obtain the

Results and discussion

Fig. 1 shows the XRD patterns of the as-synthesized Zn_1−xY_xO (x = 0.00, 0.01, 0.03, 0.05, 0.07) and x = 0.09 inset in it. For Zn_1−xY_xO (0.00 ≤ x ≤ 0.07), all the diffraction peaks can be indexed to a wurtzite structure of ZnO which belongs to $C_{6 v}^{4}$ space group (P63mc). No diffraction peaks from any other chemical species such as yttrium oxides were detected within the sensitivity of XRD. For Zn_1−xY_xO with x = 0.09, a peak near the peak of Zn_1−xY_xO (1 0 0) plane emerges, as shown in the insert in Fig. 1. As

Conclusions

1.
Y-doped ZnO nanopaticals with particle size of about 40–60 nm were synthesized by the sol–gel method and Y ions were successfully incorporated into ZnO lattice, testified by XRD and XPS spectra.
2.
Doping of Y element into the ZnO lattice induces the increase of lattice constant and the broadening of diffraction peak. By analyzing the XRD pattern, the saturation doping concentration of Y in ZnO lattice is estimated to be about 6.12 at%, above this concentration, Y₂O₃ phase forms in the powder sample.
3.

Acknowledgments

This work was supported by National Nature Science Foundation (Grant no. 50871046), the Foundation of National Key Basic Research and Development Program (no. 2010CB631001) and the Applications of Environmental Friendly Materials from the Key Laboratory Ministry of Education, Jilin normal University.

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Enhanced UV emission of Y-doped ZnO nanoparticles

Abstract

Highlights

Introduction

Section snippets

Experimental

Results and discussion

Conclusions

Acknowledgments

Applied Physics Letters

Journal of Physical Chemistry C

Nano Letters

Chemistry of Materials

Journal of Physical Chemistry B

Advanced Materials

Journal of Applied Physics

Optical Materials

Journal of Applied Physics

Journal of Physical Chemistry C

Journal of Alloys and Compounds

Journal of Applied Physics

Physica E