Optical transmission and laser structuring of silicon membranes

Saulius Juodkazis,Paul Leiderer,Hiroaki Misawa,Olivier Schecker,Reimar Waitz,Yasufumi Nishi,Elke Scheer,Vygantas Mizeikis

doi:10.1364/oe.17.015308

Abstract

The optical linear and nonlinear properties of ~ 340-nm thick Si membranes were investigated. The investigation included both experiments in which the reflection and transmission from the membranes were measured, and finite differences time domain simulations. The linear optical transmission of the Si membranes can be controlled by changing the thickness of a thermally grown oxide on the membrane. Illumination of the membranes with high levels of irradiation leads to optical modifications that are consistent with the formation of amorphous silicon and dielectric breakdown. When irradiated under conditions where dielectric breakdown occurs, the membranes can be ablated in a well-controlled manner. Laser micro-structuring of the membranes by ablation was carried out to make micrometer-sized holes by focused fs-pulses. Ns-pulses were also used to fabricate arrays of holes by proximity-ablation of a closely-packed pattern of colloidal particles.

Highlights

Nano-structures and nano-devices have at least one cross section smaller or comparable with 100 nm
Thermal oxidation of the membranes allows tuning the thickness of silicon via formation of an oxide layer [14, 15]
We optically characterized silicon membranes prepared by wet etching and subsequent controlled thermal oxidation

Summary

Introduction

Nano-structures and nano-devices have at least one cross section smaller or comparable with 100 nm. There is an increasing demand for nano-materials which could be incorporated and integrated into hierarchically larger structures of a sub-millimeter scale. These structures could be used for new applications in the fields of electronics [1, 2], micro-electro-mechanical systems (MEMS) and their optical counterparts (MOEMS). A particular type of nano-materials are membranes, which have thicknesses of ∼ 100 nm and lateral dimensions that can be up to 104 times larger than their thickness They serve as molecular sieves [3] and for slab photonic crystals [4, 5]. This makes them attractive for MOEMS and microfluidic applications [10]

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Results

Conclusion