Micro- and Nano-structured Metal Films for Optoelectronic Devices

Sammanfattning: Two types of micro and nanostructures of metal-dielectric films have been explored with the intention of improving optoelectronic devices.The first part of the thesis concerns the design, fabrication and characterization of a metallic photonic crystal (mPhC). The mPhC was investigated with respect to fill factor, pitch size, metal thickness and bulk material to improve potential detectivity and responsivity when integrated on quantum dot infrared photo detectors (QDIPs). The pitch size was found to be the most important factor for the peak wavelength position of the bandpass while the bandwidth of the bandpass is formed by the combination of fill factor and metal thickness. The choice of substrate material was shown to only have a slight effect on the peak wavelength position through a positive relation with the refractive index of the substrate material.In the second part of the thesis a thin-film multilayer optical resonator structure is explored with regards to its suitability as a transparent conductor. The structure was designed with a transfer matrix method. The figure of merit given by the transmissivity-over-resistance of the fabricated structure was shown to compare favorably to the notably common indium-tin-oxide (ITO) alloy currently used in optoelectronic applications as a transparent conductor. Although limited in transmission bandwidth, the silver-based multilayer structure can be valuable for optoelectronic applications and potentially replacing ITO owing to its relatively high peak transmissivity, improved conductivity as well as decreased fabrication costs.