Enhancement of Photoluminescence Lifetime of ZnO Nanorods Making Use of Thiourea

Kadem Meral,Erdal Sönmez

doi:10.1155/2012/957035

Abstract

We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO) nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S). Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic spray pyrolysis technique. The as-prepared specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and time-resolved photoluminescence spectroscopy (TRPL). The photoluminescence lifetime of ZnO nanorods and ZnO nanorods containing thiourea was determined as ns and ns , respectively. The calculated lifetime values of ZnO nanorods revealed that the presence of thiourea in ZnO nanorods resulted in increasing the exciton lifetime. In addition to the optical quality of ZnO nanorods, their exciton lifetime is comparable to the longest lifetimes reported for ZnO nanorods. The structural improvement of ZnO nanorods, containing thiourea, was also elucidated by taking their SEM images which show the thinner and longer ZnO nanorods compared to those without thiourea.

Highlights

Zinc oxide (ZnO) is a wide-band gap (Eg ≈ 3.37 eV at 300 K) semiconductor with good carrier mobility and can be doped n-type or p-type
scanning electron microscopy (SEM) images demonstrated that the nanorod structures of ZnO on the glass substrate were formed at 550◦C
It can be seen the SEM images (Figure 1) that this deposition temperature is suitable for the formation of ZnO nanorods without or with thiourea

Summary

Introduction

Zinc oxide (ZnO) is a wide-band gap (Eg ≈ 3.37 eV at 300 K) semiconductor with good carrier mobility and can be doped n-type or p-type. Different deposition methods have been developed to fabricate a variety of ZnO nanostructures such as wellknown metal organic chemical vapor [28, 29], pulsed laser [30, 31], electrochemical deposition techniques [32, 33], vapor-liquid, solid [34, 35], and wet chemical methods [36,37,38] In addition to those methods, the important one is chemical spray pyrolysis system which is one of the most elegant methods to the preparation of good-quality ZnO nanostructures. This method has several advantages over the other methods such as providing short time, being costeffective and template-free [39]. The results showed that the exciton lifetime of ZnO nanorods was increased in the presence of thiourea

Experimental

Results and Discussion

Conclusion