Abstract: We present the characterization of a dry-etching process for high-contrast TiO2/SiO2 distributed Bragg reflectors, by inductively coupled plasma reactive ion etching, focusing on the etch rate and the etch selectivity. Photoresists and metals as etch masks were investigated. An excellent etch profile using an indium tin oxide mask was obtained, with an etch rate of >80 nm/min at a pressure of 6 mTorr. The experiments were developed for structuring Fabry–P´erot filters for tunable optical sensor arrays.
Notes: Received 1 April 2010; revised 25 September 2010; accepted 14 October 2010; published 28 December 2010
Abstract: An advanced optical setup is presented for measuring transmission and reflection spectra (400 nm to 900 nm) with high spatial and spectral resolution for optical nano sensor arrays. Advantages of the methodology and latest results are discussed such as Full Width at Half Maxima (FWHM) and bandwidth.
Abstract: We have investigated the etching characteristics of high-index-contrast TiO2/SiO2 DBR mirrors by inductively coupled plasma reactive ion etching (ICP-RIE) with a focus on the etch rate and the etch selectivity by varying etch parameters (gas flow rate, RF and ICP power, pressure and temperature). Chrome, aluminum and ITO (indium tin oxide) were applied as etch masks. Various mixtures of SF6/Ar gas were used for the etch processes. An optimum etch profile was obtained with an etch rate of approximately 80 nm/min at a pressure of 6 mTorr and a temperature of 20 °C. The experimental results were applied to develop Fabry-Perot filters for tunable optical sensor arrays.
Abstract: Micro-opto-electromechanical systems (MOEMS) based on micromechanical mirrors can be used as key elements for light guiding, steering and concentration. We propose micromechanical mirror arrays for light concentration on photovoltaic modules. The semiconductor materials for solar cells are the most expensive components of a photovoltaic system. One of the ways to reduce cost is to use light concentration by focusing sunlight onto small solar cell areas using optical components such as lens systems. The whole system requires an external rotation mechanism to track the suns position. As an alternative, we propose and implemented micromachined mirror arrays to concentrate light. This allows precise dynamic light steering onto the solar cell module. These micromirror arrays can be electrostatically tuned to track the sun position or the maximum of the brightness distribution in the sky. The micromirror arrays are located in a sealed environment and, therefore, insensitive to external influences, such as atmosphere and wind. The advantages of the micromachined mirrors based concentrator photovoltaic systems are dynamic light steering onto solar cells, mass production compatibility, long lifetime and low cost. The concept of the micromachined mirror arrays will be presented.
Notes:
invited article in Fachzeitschrift (professional journal)
