Simulation and analysis of photonic structures in macroporous silicon

This Master Thesis is dedicated to photonic crystal, in particular to macroporous silicon. We introduce the concepts of crystallography, and symmetry, and important associated tools to its study, the Reciprocal lattice, and the Brillouin Zone. We also give a brief explanation of anodic macropore formation in silicon; the method used in-site to produce photonic crystals. It follows a section explaining Fourier Transform spectrometry, and how it was used in the present work. Following it, we introduce our main software tools, which we have learned and used extensively throughout the development of this Thesis. We go into certain detail, to point some important aspects, or simply to provide a quick use guide. We finally present the results of our measures and simulations, the comparisons made and the conclusion that we can extract from our experiments

Macroporous Silicon: Technology and Applications

Macroporous silicon (MPS) is a versatile material that since its origin in the early 1990s has seen intense research and has found applications in many fields. MPS is a key technology in photonic crystals research, and optic and photonic applications are its main applications. However, this chapter is devoted to several of the non‐photonic uses of MPS. In particular, new electronic and MEMS devices and applications will be described. Furthermore, in this chapter, the technology of MPS fabrication will be presented

Study of resonant modes in a 700 nm pitch macroporous silicon photonic crystal

In this study the modes produced by a defect inserted in a macroporous silicon (MP) photonic crystal (PC) have been studied theoretical and experimentally. In particular, the transmitted and reflected spectra have been analyzed for variations in the defect’s length and width. The performed simulations show that the resonant frequency is more easily adjusted for the fabricated samples by length tuning rather than width. The optimum resonance peak results when centered in the PC bandgap. The changes in the defect geometry result in small variations of the optical response of the PC. The resonance frequency is most sensitive to length variations, while the mode linewidth shows greater change with the defect width variation. Several MPS photonic crystals were fabricated by the electrochemical etching (EE) process with optical response in the range of 5.8 µm to 6.5 µm. Results of the characterization are in good agreement with simulations. Further samples were fabricated consisting of ordered modulated pores with a pitch of 700 nm. This allowed to reduce the vertical periodicity and therefore to have the optical response in the range of 4.4 µm to 4.8 µm. To our knowledge, modes working in this range of wavelengths have not been previously reported in 3-d MPS structures. Experimental results match with simulations, showing a linear relationship between the defect’s length and working frequency inside the bandgap. We demonstrate the possibility of tailoring the resonance peak in both ranges of wavelengths, where the principal absorption lines of different gases in the mid infrared are placed. This makes these structures very promising for their application to compact gas sensors.Postprint (author's final draft

Macroporous silicon for high-capacitance devices using metal electrodes

Peer ReviewedPostprint (published version

Macroporous silicon for high-capacitance devices using metal electrodes

Peer ReviewedPostprint (published version

Transmission and thermal emission in the NO2 and CO absorption lines using macroporous silicon photonic crystals with 700 Nm pitch

Postprint (author's final draft

Impact of the absorption in transmittance and reflectance on macroporous silicon photonic crystals

The characteristics of reflection and transmission peaks in the spectra of photonic crystals have been studied theoretically and the results compared to measurements performed in fabricated samples. The aim of this work is to investigate the relation between material losses and the effective Q factors that can be obtained in photonic crystals made with it. Photonic crystals have been designed with defects of periodicity to introduce states in the band gap that give place to reflectance and transmittance peaks at adjustable specific wavelengths. The fabricated structures are described together with their reflection and transmission spectra. The influence of losses in the material in these spectra is evaluated.Postprint (published version

Simulation and analysis of photonic structures in macroporous silicon

This Master Thesis is dedicated to photonic crystal, in particular to macroporous silicon. We introduce the concepts of crystallography, and symmetry, and important associated tools to its study, the Reciprocal lattice, and the Brillouin Zone. We also give a brief explanation of anodic macropore formation in silicon; the method used in-site to produce photonic crystals. It follows a section explaining Fourier Transform spectrometry, and how it was used in the present work. Following it, we introduce our main software tools, which we have learned and used extensively throughout the development of this Thesis. We go into certain detail, to point some important aspects, or simply to provide a quick use guide. We finally present the results of our measures and simulations, the comparisons made and the conclusion that we can extract from our experiments

Macroporous silicon. Technology and applications

The knowledge of fundamental silicon questions and all aspects of silicon technology gives the possibility of improvement to both initial silicon material and devices on silicon basis. The articles for this book have been contributed by the much respected researchers in this area and cover the most recent developments and applications of silicon technology and some fundamental questions. This book provides the latest research developments in important aspects of silicon including nanoclusters, solar silicon, porous silicon, some technological processes, and silicon devices and also fundamental question about silicon structural perfection. This book is of interest both to fundamental research and to practicing scientists and also will be useful to all engineers and students in industry and academia.Peer Reviewe

Managing voluntary organisations A study of role issues amongst chairs and managers in British voluntary organisations

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN035351 / BLDSC - British Library Document Supply CentreGBUnited Kingdo