Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Engineering Science

School

Electron Science Research Institute

Faculty

Health, Engineering and Science

First Advisor

Professor Kamal Alameh

Second Advisor

Dr Mikhail Vasiliev

Abstract

This thesis focuses on the design and development of silver nanoparticles that can be used as masks for the development of antireflection subwavelength grating (SWG) structures. We particularly investigate the impact of silver thin film thickness and the effect of annealing temperature on the fabrication of silver nanoparticles of controlled size and spacing distributions. We also use these measured distributions to predict the performance of subwavelength grating structures developed using dry and isotropic etching of semiconductor substrates.

Silver (Ag) thin films of different thicknesses are deposited on Silicon (Si) and Gallium Arsenide (GaAs) semiconductor substrates and annealed at different temperatures. Uniform nanoparticles with diameters around 200nm and spacing between nanoparticles as low as possible are our target as these parameters are suitable for the fabrication of antireflection SWG structures, having grating widths equal to the nanoparticle diameter and spacing equals to the spacing between nanoparticles. Experimental results demonstrate that by annealing the Ag thin films with different temperature profiles, it is feasible to develop Ag nanoparticles, of diameter around 200nm and spacing below 250nm, at most of the annealing temperatures investigated.

In addition, different subwavelength structures, developed by etching the Ag nanoparticles deposited on Si and GaAs substrates, are simulated using a Finite- Difference Time Domain (FDTD) software package. The simulation results show that substantial reduction in light reflection can be achieved by optimizing the height of the subwavelength structures through the control of the etching time.

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