Fabrication

About: Fabrication is a research topic. Over the lifetime, 20475 publications have been published within this topic receiving 235676 citations.

Integration of active and passive polymer optics.

Abstract: We demonstrate a wafer scale fabrication process for integration of active and passive polymer optics: Polymer DFB lasers and waveguides. Polymer dye DFB lasers are fabricated by combined nanoimprint and photolithography (CNP). The CNP fabrication relies on an UV transparent stamp with nm sized protrusions and an integrated metal shadow mask. In the CNP process, a combined UV mask and nanoimprint stamp is embossed into the resist, which is softened by heating, and UV exposed. Hereby the mm to μm sized features are defined by the UV exposure through the metal mask, while nm-scale features are formed by mechanical deformation (nanoimprinting). The lasers are integrated with undoped SU-8 polymer waveguides. The waferscale fabrication process has a yield above 90% and the emission wavelengths are reproduced within 2 nm. Confinement of the light on the chip is demonstrated, and the influence on the laser wavelength from temperature and refractive index changes in the surroundings is investigated, pointing towards the use of the described fabrication method for on-chip polymer sensor systems.

Epitaxial growth of sexi-thiophene and para-hexaphenyl and its implications for the fabrication of self-assembled lasing nano-fibres

Abstract: Over the last few years, epitaxially grown self-assembled organic nano-structures became of increasing interest due to their high potential for implementation within opto-electronic devices. Exemplarily, the epitaxial growth of the rod-like molecules para-hexaphenyl (p-6P) and α-sexi-thiophene (6T) is discussed within this review. Both molecules tend to crystallize in highly asymmetric elongated entities which are also called nano-fibres. It is demonstrated that the obtained needle orientations and morphologies result from a complex interplay between various parameters e.g. substrate surface symmetry, molecular adsorption, crystal structure and contact plane. The interplay and its implications on the fabrication of self-assembled waveguiding nano-fibres and optical resonator structures are discussed and substantiated by a comparison with the reported literature. In further consequence, it is demonstrated that a precise control on the molecular adsorption geometry and the crystal contact plane represents a fundamental key parameter for the fabrication of self-assembled nano-fibres. As both parameters are basically determined by the chosen molecule–substrate material couple, the possible spectrum of molecular building blocks for the fabrication of waveguiding and lasing nano-structures can be predicted by the discussed growth model. A possible expansion of this common valid concept is presented by the utilization of organic–organic heteroepitaxy. Based on the reported p-6P/6T heterostructures which have been fabricated on various substrate surfaces, it is substantiated that the fabrication of organic–organic interfaces can be effectively used to gain control on the molecular adsorption geometry. As the proposed strategy still lacks a precise control of the obtained crystal contact plane, further strategies are discussed which potentially lead to a controlled fabrication of opto-electronic devices based on self-assembled organic nano-structures.

A review on fabrication processes for electrochromic devices

Abstract: Electrochromism is a phenomenon involving change of colors under an externally applied voltages Because its importance is rising today, various fabrication processes have been used to manufacture electrochromic devices (ECDs). In this review, solution-, vapor-, and solid particle-based processes are introduced and compared in terms of process parameters. The seven representative fabrication processes discussed in this paper are electrodeposition, sol-gel, spray pyrolysis, chemical vapor deposition (CVD), thermal evaporation deposition, sputtering, and nanoparticle deposition systems (NPDS). Temperature and vacuum conditions for each process are compared. Electrodeposition and sol-gel processes can be performed under atmospheric pressure. Most sputtering and NPDS processes are conducted at room temperature. Although many fabrication processes are reviewed here, commercialization, environmental issues, cost, improvement of performance, and enhancement of product size will be studied for future ECDs.