By means of electrochemical treatment, crystalline silicon can be permeated with tiny, nanostructured pores that entirely change the characteristics and properties of the material. One prominent example of this can be seen in the interaction of porous silicon with living cells, which can be totally unwilling to settle on smooth silicon surfaces but readily adhere to porous silicon, giving rise to great hopes for such future applications as programmable drug delivery or advanced, braincontrolled prosthetics. Porous silicon research is active in the fields of sensors, tissue engineering, medical therapeutics and diagnostics, photovoltaics, rechargeable batteries, energetic materials, photonics, and MEMS (Micro Electro Mechanical Systems). Written by an outstanding, well-recognized expert in the field, this book provides detailed, step-by-step instructions to prepare and characterize the major types of porous silicon. It is intended for those new to the fi eld. Sampling of topics covered: * Principles of Etching Porous Silicon * Etch Cell Construction and Considerations * Photonic Crystals, Microcavities, and Bragg Stacks Etched in Silicon * Preparation of Free-standing Films and Particles of Porous Silicon * Preparation of Photoluminescent Nanoparticles from Porous Silicon * Preparation of Silicon Nanowires by Electrochemical Etch of Silicon * Surface Modifi cation Chemistry and Biochemistry * Measurement of Optical Properties * Measurement of Pore Size, Porosity, Thickness, Surface Area The whole is backed by a generous use of color photographs to illustrate the described procedures in detail, plus a bibliography of further literature pertinent to a wide range of application fi elds. For materials scientists, chemists, physicists, optical physicists, biomaterials scientists, neurobiologists, bioengineers, and graduate students in those fields, as well as those working in the semiconductor industry.

Einen verständlichen Zugang zum Thema bietet dieser Band und wendet sich an Praktiker ebenso wie an Studierende und Wissenschaftler. Er macht u. a. vertraut mit elektrochemischen Methoden und der Anwendung von Materialien, die zur Herstellung von porösem Silizium notwendig sind.

PrefaceFUNDAMENTALS OF POROUS SILICON PREPARATIONIntroductionChemical Reactions Governing the Dissolution of SiliconExperimental Set-up and Terminology for Electrochemical Etching of Porous SiliconElectrochemical Reactions in the Silicon SystemDensity, Porosity, and Pore Size DefinitionsMechanisms of Electrochemical Dissolution and Pore FormationResume of the Properties of Crystalline SiliconChoosing, Characterizing, and Preparing a Silicon WaferPREPARATION OF MICRO-, MESO-, AND MACRO-POROUS SILICON LAYERSEtch Cell: Materials and ConstructionPower SupplyOther SuppliesSafety Precautions and Handling of WastePreparing HF Electrolyte SolutionsCleaning Wafers Prior to EtchingPreparation of Microporous Silicon from a p-Type WaferPreparation of Mesoporous Silicon from a p++-Type WaferPreparation of Macroporous, Luminescent Porous Silicon from an n-Type Wafer (Frontside Illumination)Preparation of Macroporous, Luminescent Porous Silicon from an n-Type Wafer (Back Side Illumination)Preparation of Porous Silicon by Stain EtchingPreparation of Silicon Nanowire Arrays by Metal-Assisted EtchingPREPARATION OF SPATIALLY MODULATED POROUS SILICON LAYERSTime-Programmable Current SourcePore Modulation in the z-Direction: Double LayerPore Modulation in the z-Direction: Rugate FilterMore Complicated Photonic Devices: Bragg Stacks, Microcavities, and Multi-Line Spectral FiltersLateral Pore Gradients (in the x-y Plane)Patterning in the x-y Plane Using Physical or Virtual MasksOther Patterning MethodsFREESTANDING POROUS SILICON FILMS AND PARTICLESFreestanding Films of Porous Silicon-"Lift-offs"Micron-Scale Particles of Porous Silicon by Ultrasonication of Lift-off FilmsCore-Shell (Si/SiO2) Nanoparticles of Luminescent Porous Silicon by UltrasonicationCHARACTERIZATION OF POROUS SILICONGravimetric Determination of Porosity and ThicknessElectron Microscopy and Scanned Probe Imaging MethodsOptical Reflectance MeasurementsPorosity, Pore Size, and Pore Size Distribution by Nitrogen Adsorption Analysis (BET, BJH, and BdB Methods)Measurement of Steady-State Photoluminescence SpectraTime-Resolved Photoluminescence SpectraInfrared Spectroscopy of Porous SiliconCHEMISTRY OF POROUS SILICONOxide-Forming Reactions of Porous SiliconBiological Implications of the Aqueous Chemistry of Porous SiliconFormation of Silicon-Carbon BondsThermal Carbonization ReactionsConjugation of Biomolecules to Modified Porous SiliconChemical Modification in Tandem with EtchingMetallization Reactions of Porous SiliconAPPENDIX A1. ETCH CELL ENGINEERING DIAGRAMS AND SCHEMATICSStandard or Small Etch Cell-CompleteStandard Etch Cell Top PieceSmall Etch Cell Top PieceEtch Cell Base (for Either Standard or Small Etch Cell)Large Etch Cell-CompleteLarge Etch Cell Top PieceLarge Etch Cell BaseAPPENDIX A2. SAFETY PRECAUTIONS WHEN WORKING WITH HYDROFLUORIC ACIDHydrofluoric Acid HazardsFirst Aid Measures for HF ContactNote to PhysicianHF Antidote GelAPPENDIX A3. GAS DOSING CELL ENGINEERING DIAGRAMS AND SCHEMATICSGas Dosing Cell Top PieceGas Dosing Cell Middle PieceGas Dosing Cell Bottom Piece