Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

Roslan Md Nor,Chiow San Wong,Tamil Many K Thandavan,Yogendra Kumar Mishra,Siti Meriam Abdul Gani

doi:10.1371/journal.pone.0121756

Abstract

Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn -), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo +) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

Highlights

The native nature of zinc oxide (ZnO) as an intrinsic n-type semiconductor has embarked several favorable properties, including good transparency, high electron mobility 2000 cm2/(Vs) at 80 K [1], wide band gap 3.37 eV and strong room temperature luminescence [2]
The x-ray diffraction (XRD) profile strongly shows various crystalline natures of Aldoped ZnO NSs compared to the un-doped ZnO NSs
Al-doped and un-doped ZnO NSs were successfully prepared on Si substrate using the Vapor phase transport (VPT) of mixture of methanol and acetone via thermal evaporation of Zn from two-sided hollow CuZn alloy

Summary

Introduction

The native nature of zinc oxide (ZnO) as an intrinsic n-type semiconductor has embarked several favorable properties, including good transparency, high electron mobility 2000 cm2/(Vs) at 80 K [1], wide band gap 3.37 eV and strong room temperature luminescence [2]. Significant changes in the intensity and FWHM were noticed from the three dominant peaks (100), (002) and (101) which could be due to the effect of Al doping into the nanostructures of ZnO NSs [37]. All the Al-doped ZnO NSs samples show higher intensity compared to the un-doped ZnO NSs. reduction in the PL intensity of GL band was observed as the Al concentration increased [19].

Results

Conclusion