Reconstructing charge-carrier dynamics in porous silicon membranes from time-resolved interferometric measurements

We performed interferometric time-resolved simultaneous reflectance and transmittance measurements to investigate the carrier dynamics in pump-probe experiments on thin porous silicon membranes. The experimental data was analysed by using a method built on the Wentzel-Kramers-Brillouin approximation and the Drude model, allowing us to reconstruct the excited carriers’ non-uniform distribution in space and its evolution in time. The analysis revealed that the carrier dynamics in porous silicon, with ~50% porosity and native oxide chemistry, is governed by the Shockley-Read-Hall recombination process with a characteristic time constant of 375 picoseconds, whereas diffusion makes an insignificant contribution as it is suppressed by the high rate of scattering

Controlling interferometric properties of nanoporous anodic aluminium oxide

A study of reflective interference spectroscopy [RIfS] properties of nanoporous anodic aluminium oxide [AAO] with the aim to develop a reliable substrate for label-free optical biosensing is presented. The influence of structural parameters of AAO including pore diameters, inter-pore distance, pore length, and surface modification by deposition of Au, Ag, Cr, Pt, Ni, and TiO2 on the RIfS signal (Fabry-Perot fringe) was explored. AAO with controlled pore dimensions was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid at different voltages (30 to 70 V) and anodization times (10 to 60 min). Results show the strong influence of pore structures and surface modifications on the interference signal and indicate the importance of optimisation of AAO pore structures for RIfS sensing. The pore length/pore diameter aspect ratio of AAO was identified as a suitable parameter to tune interferometric properties of AAO. Finally, the application of AAO with optimised pore structures for sensing of a surface binding reaction of alkanethiols (mercaptoundecanoic acid) on gold surface is demonstrated

Porous Silicon Functionalities for BioMEMS

This chapter presents a literature survey of the applications of porous silicon in BioMEMS (biological/biomedical microelectromechanical systems). This material possesses properties particularly suitable for biomedical purposes: biocompatibility, biodegradability, photoluminescence, ability to precisely control the pore size and shape, and possibility to easily modify the surface chemistry. Many applications can, for instance, be found in the fields of sensing and delivery of therapeutics. It is expected that the number of BioMEMS using porous silicon will continue to increase in the future with the development of lab-on-a-chip/ microfluidic devices.SCOPUS: ch.binfo:eu-repo/semantics/publishe

Porous silicon functionalities for BioMEMS

This chapter presents a literature survey of the applications of porous silicon in BioMEMS (biological/biomedical microelectromechanical systems). This material possesses properties particularly suitable for biomedical purposes: biocompatibility, biodegradability, photoluminescence, ability to precisely control the pore size and shape, and possibility to easily modify the surface chemistry. Many applications can, for instance, be found in the fields of sensing and delivery of therapeutics. It is expected that the number of BioMEMS using porous silicon will continue to increase in the future with the development of lab-on-a-chip/ microfluidic devices.SCOPUS: ch.binfo:eu-repo/semantics/publishe