A feedback control mechanism based on infrared radiation monitoring coupled with reflectivity information was developed to control the temperature of a laser assisted chemical vapor deposition process for the growth of carbon nanotube forests. An infrared laser operating at 808 nm is focused on a silicon substrate containing a 20 nm-aluminum-oxide layer and a 1.5 nm-iron catalyst layer. The growth takes place in an argon/ hydrogen/ ethylene gaseous environment. SEM and Raman spectroscopy analysis show that good controllability and reproducibility is achieved over multiple experiments.

Femtosecond laser irradiation has various noticeable effects on fused silica. It can locally increase the index of refraction or modify the material chemical selectivity. Regions that have been exposed to the laser are etched several times faster than unexposed regions. Various observations reported in the literature seem to show that these effects are possibly related to a combination of structural changes and the presence of internal stress. However, a detailed analysis of the contribution of both effects is still lacking.

In this paper, we present systematic SEM-based investigations performed on fused silica (a-SiO2). Line-patterns were first scanned on the substrate using a femtosecond laser and then etched in a low-concentration HF solution. The effects of various laser parameters like power and scanning speed are analyzed and we show further evidence of an interface between two different etching regimes.

When deposited at room temperature, sputtered NiTi thin films are amorphous and need to be crystallized before they can be used as a functional material. We present the results of an annealing study on substrate-constrained NiTi shape memory thin films. Amorphous films of a NiTi shape memory alloy were deposited by UHV sputtering. Films of thickness 1.0 μm were grown on (100) Si wafers both with and without an LPCVD SiNx barrier. The as-deposited films were annealed in vacuum at temperatures ranging from 500°C to 800°C. The microstructure of the annealed films was characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and Rutherford back scattering (RBS).

This paper presents dramatic improvements in the micro-fabrication of three-dimensional microfluidic channels and high-aspect ratio tunnels within the bulk of a fused silica substrate. We also report the fabrication of optical waveguides within the same substrate, which is a major step towards the integration of sensing capabilities within microfluidic networks.

This integrated device, which combines both fluidic channels and optical waveguides, opens new opportunities in bio- and chemical sensing. The flexibility of the improved manufacturing process offers substantial new design capabilities, especially for single channel probing and massively parallel processing and sensing.