Transcript Document

Porous Silicon: a novel nanomaterial
By
Suchitra Ramani
ECEN, OSU
Porous Silicon: Fabrication
 Discovered
at Bell labs by Uhlir in 1956
 Two methods:1)Electrochemical anodization of bulk Si (p/n type)
2)Stain etching
+
-
HF resistant
cell
Pt cathode
HF + ethanol
Si wafer
Metal back
contact
R. L. Smith and S. D. Collins, J. Appl. Phys. 71, R1 (1992)
Porous Silicon: Features
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Silicon sponge - Disordered nanostructure
Large surface area ~ 600 m2 /cm3
Types:
Microporous < 2nm
Mesoporous (2 -50)nm
Macroporous > 50nm
Photoluminescence in the visible region : Eg~1.4 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
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
Drug delivery
Gas sensor
Georgia Inst. of Tech
BiosiliconTM
Microcavity
Univ. of Rochester