Porous Silicon: a novel nanomaterial

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Porous Silicon a novel nanomaterial By Suchitra
Ramani ECEN, OSU
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Porous Silicon Fabrication

• Discovered at Bell labs by Uhlir in 1956
• Two methods1)Electrochemical anodization of bulk
  Si (p/n type) 2)Stain
  etching

Pt cathode
Metal back contact
R. L. Smith and S. D. Collins, J. Appl. Phys. 71,
R1 (1992)
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Porous Silicon Features

• Silicon sponge - Disordered nanostructure
• Large surface area 600 m2 /cm3
• Types
• Microporous lt 2nm
• Mesoporous (2 -50)nm
• Macroporous gt 50nm
• Photoluminescence in the visible region Eg1.4
  to 2eV
• PS layer porosity, thickness and morphology
  tailored with HF concentration, anodization time
  and current density
• Quantum confinement
• Ageing by exposure to ambient air

Bernard Gauthier-Manuel and Tristan Pichonat
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Current research and Potential applications

• Microcavity
• Broadband AR coating
• LED
• for THz
• Chemical Sensors
• Smart Dust
• Pressure Sensor
• Photonic crystal
• Biosensor for pathogen
• detection, detection of Toxins

Gas sensor
Drug delivery
Georgia Inst. of Tech
BiosiliconTM
Microcavity
Univ. of Rochester