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Growth of Zinc Oxide Crystals and Their Scintillation Properties
|Yuji Kagamitani 1, Dirk Ehrentraut 1, Jan Pejcha 2, Martin Nikl 2, Hideho Odaka 3, Akira Yoshikawa 1, Hiroshi Fukumura 3, Tsuguo Fukuda 1|
1. Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Sendai 980-8577, Japan
ZnO is a wide band-gap semiconductor (Eg = 3.37 eV) with a high exciton binding of 60 meV. It has great potential for application in optoelectronics, piezoelectricity, and UV-blue LED. Since exciton luminescence of ZnO shows very short decay time of < 1 ns, it is attractive as ultra-fast scintillator material. However intensity of exciton luminescence of ZnO for device application is relatively low because of following reasons:
In this study, comparison of scintillation properties of ZnO with different surface quality was performed. Moreover, growth and effect of donors on red-shift of the luminescence wavelength was examined in details in order to decrease self-absorption.
ZnO crystals were grown by hydrothermal method from Pt container and liquid phase epitaxy (LPE) with LiCl flux. Photoluminescence spectra at room temperature were measured with Xe lamp excitation and S900 spectrometer (Edinburgh Instruments). For decay time measurement, fs laser CPA2001 (Clark-MXR) was used as an excitation source. (260 nm, 160fs).
The as grown ZnO epitaxial layers with untreated surface show highest emission intensity from the band edge, and defect-related luminescence was low. It was also confirmed that exciton luminescence of ZnO can be increased by improving after-growth machining of the crystals. Exciton luminescence of In3+-doped ZnO was shift to longer wavelength range (398 nm). In:ZnO crystals demonstrated ultra-short decay of two components (40 ps and 650ps).
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium F, by Yuji Kagamitani
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-07-11 04:09 Revised: 2009-06-07 00:44