Optical Properties of Si Quantum Dots in Silica via an Implantation Mask
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1208-O07-05
Optical Properties of Si Quantum Dots in Silica via an Implantation Mask Eric G. Barbagiovanni, Lyudmila V. Goncharova, P. J. Simpson and Nathan Armstrong Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada, N6A 3K7 ABSTRACT We studied photoluminescent properties and luminescent decay dynamics in Si quantum dots (QDs) produced by Si implantation in SiO2, and their modification by the application of an implantation mask. Silicon quantum dots were prepared by ion implantation, followed by high temperature annealing leading to nanocrystal nucleation and growth. The mask was prepared by spin-coating silica microspheres to achieve laterally-selective implantation, to control QD size and separation. Transmission electron microscopy (TEM) images were obtained to verify the diameter of the quantum dots. We observe a noticeable peak shift and narrowing in the photoluminescence spectra with the application of the implantation mask. Observed maxima in the photoluminescence spectra are compared with a quantum field theoretical model using an infinite confining 1D potential for Si quantum dots. We comment on the role of excitation transfer by observing a change in the dispersion exponent of the luminescent decay dynamics due to the mask. INTRODUCTION Considerable effort has been spent in investigating the structural, electronic and optical properties of silicon nanostructures. In particular, low dimensional structures with silicon quantum dots embedded in an SiO2 matrix have drawn much attention due to their interesting luminescent properties and their compatibility with standard silicon processing technologies, such as implantation and thermal treatments. Quantum dots (QDs) produced by ion implantation are primarily controlled by a few parameters: implantation dose, implantation energy and annealing conditions [1]. In addition, implantation geometry, pre-implantations to create disorder, multiple implant conditions and temperature during implantation can be considered. The annealing conditions also determine the size of the QDs [2]. In the first moments of annealing (
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