Porous Silicon—A Versatile Host Material

Abstract

This work reviews the use of porous silicon (PS) as a nanomaterial which is extensively investigated and utilized for various applications, e.g., in the fields of optics, sensor technology and biomedicine. Furthermore the combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Such nanocompounds offer a broad avenue of new and interesting properties depending on the kind of involved materials as well as on their morphology. The filling of the pores performed by electroless or electrochemical deposition is described, whereas different morphologies, reaching from micro- to macro pores are utilized as host material which can be self-organized or fabricated by prestructuring. For metal-deposition within the porous structures, both ferromagnetic and non-magnetic metals are used. Emphasis will be put on self-arranged mesoporous silicon, offering a quasi-regular pore arrangement, employed as template for filling with ferromagnetic metals. By varying the deposition parameters the precipitation of the metal structures within the pores can be tuned in geometry and spatial distribution leading to samples with desired magnetic properties. The correlation between morphology and magnetic behaviour of such semiconducting/magnetic systems will be determined. Porous silicon and its combination with a variety of filling materials leads to nanocomposites with specific physical properties caused by the nanometric size and give rise to a multiplicity of potential applications in spintronics, magnetic and magneto-optic devices, nutritional food additives as well as drug delivery.

Heat transport in phononic-like membranes: Modeling and comparison with modulated nano-wires

“…Silicon is the most common semi-conductor 5 on Earth and is a non-pollutant material. Therefore, nano-structured Silicon has been intensively studied experimentally and theoretically for its optical [3,4] or thermal properties [5, 6,7] among a plethora of other properties. The importance of thermal management of nano-structures has arisen as the electronic devices became smaller and more powerful.…”

Characteristic length of phonon transport within periodic nanoporous thin films and two-dimensional materials

“…In recent years, nanoporous thin films have been widely studied for their potential applications in thermoelectrics, 1-17 gas sensors, 18 and thermal management. [19][20][21] For thermoelectrics, the effectiveness of a material is evaluated by its thermoelectric figure of merit (ZT), defined as ZT ¼ S 2 rT/k, where S, r, k, and T represent Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively.…”

Self-Adjusting Electrochemical Etching Technique for Producing Nanoporous Silicon Membrane

“…Resistance dopants also affect the pore size based on the density of dopant. Silicon with a pore size of 2-4 nm can be formed using silicon-type n and p dopants that have low and medium density, silicon with pore size of 5-50 nm can be generated using a dopant with high density and silicon with pore size of 50 nm to several 10 m can be formed using a dopant with medium density [45]. This is because the mechanism of formation of the vent holes needs to justify the dissolution of the ion [19].…”