Title: Nanoscale growth of (Zn,Sr)S system for electron-trapping optical memories

Authors: K.L. Teo, T.C. Chong

Addresses: Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4, Engineering Drive 3, 117576, Singapore. ' Data Storage Institute, 5, Engineering Drive 1, 117608, Singapore

Abstract: In this work, we give a review on the nanoscale cubic-islands growth of SrS and Zn_xSr_1-xS [abbreviated as (ZnSr)S] thin films by solid-source molecular-beam epitaxy (MBE). Our detailed analyses of scanning electron microscopy (SEM) and atomic force microscopy (AFM) images show that different sizes of SrS islands can be achieved depending on the substrate temperature. Reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD) establish cube-on-cube (001)_SrS || (001)_MgO with [001]_SrS || [001]_MgO epitaxial relationship. All these results point towards the growth to occur in step-flow mode. When (ZnSr)S is codoped with europium and samarium ions (SrS : Eu, Sm and ZnSrS : Eu, Sm), infrared-stimulated luminescence (ISL) with a peak at 612 nm is observed at room temperature, which is stimulated with infrared light after irradiation with visible light. The ISL results show that the (ZnSr)S system can be developed for erasable and rewritable optical memory.

Keywords: SrS; ZnSrS; electron trapping; erasable optical memories; rewritable optical memories; nanoscale growth; nanotechnology; thin films; molecular-beam epitaxy; strontium sulphide.

DOI: 10.1504/IJNT.2007.013975

International Journal of Nanotechnology, 2007 Vol.4 No.4, pp.412 - 423

Published online: 05 Jun 2007 *

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