Structure and strong ultraviolet emission characteristics of amorphous ZnO films grown by electrophoretic deposition
- PDF / 146,625 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 15 Downloads / 226 Views
Shenggang Yan and Chunyan Wang School of Chemical Engineering, Dalian University of Technology Dalian, 116012 People’s Republic of China (Received 1 July 2002; accepted 17 October 2002)
Structure and ultraviolet emission characteristics of amorphous ZnO films grown on indium tin oxide coated glass substrates by electrophoretic deposition were investigated using Raman spectra and photoluminescence. The Raman spectrum shows a unique resonant multiphonon process within amorphous ZnO films. The photoluminescence spectrum of amorphous ZnO films shows a strong ultraviolet emission while the visible emission is nearly fully quenched. The transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectrum, and infrared spectrum are used to detect the structure of amorphous ZnO powder. The complex water plays an important role in the photoluminescence intensity emission.
I. INTRODUCTION
There has been great interest in wide band gap semiconductors because there is a strong commercial desire to produce efficient and lasing blue light-emitting diodes and short-wavelength laser diodes. As a wide band gap (Eg ⳱ 3.37 ev1) semiconductor material, ZnO has received an increasing amount of attention due to its possible application in ultraviolet (UV) light-emitting devices,2,3 electron-acoustic devices,4 UV detectors,5 and others.6 In recent years, there has been a great interest in the development of high-quality ZnO films to obtain strong UV emission. Several techniques are being used to produce ZnO film; e.g., metalorganic chemical vapor deposition,7 molecular beam epitaxy,8 chemical vapor deposition,9 combustion chemical vapor deposition,10 pulsed laser deposition, 11 and electrophoretic deposition (EPD).12,13 The main advantages of EPD are easy operation and no need for complex instruments. In most previous works, visible emission dominated the photoluminescence (PL) spectra of ZnO films. Few PL spectra of ZnO films with pure strong UV have been reported.14 In this article, we first report a simple and efficient method to prepare amorphous ZnO powder by solid-state pyrolytic reaction; then the amorphous ZnO films were deposited onto indium tin oxide (ITO) coated glass substrates by EPD. The amorphous ZnO displayed quasi-three-dimensional quantum confinement effects, greatly increasing the PL efficiency. PL spectra indicated J. Mater. Res., Vol. 18, No. 1, Jan 2003
http://journals.cambridge.org
Downloaded: 04 Jul 2014
that the EPD films of amorphous ZnO appeared to have strong UV emission, while that visible emission was barely observed at room temperature. II. EXPERIMENTAL A. Electrophoretic deposition of amorphous ZnO films
The preparation of amorphous ZnO films is described as the following. Deposition solution was prepared with concentration of 0.006 M amorphous ZnO and 10 −5 M of Mg(NO 3 ) 2 · 6H 2 O in isopropyl alcohol solvent. Here, preparation of amorphous ZnO powder can be briefly described as follows: 2.2 g (10 mmol) Zn(CH3COO)2 · 2H2O and 2 g (23.8 mmol) NaHCO3 were mixed at room temperature. The r
Data Loading...
