Method and apparatus for determining minority carrier diffusion length in semiconductors
- Princeton, NJ
Method and apparatus are provided for determining the diffusion length of minority carriers in semiconductor material, particularly amorphous silicon which has a significantly small minority carrier diffusion length using the constant magnitude surface-photovoltage (SPV) method. Steady or modulated illumination at several wavelengths provides the light excitation on the surface of the material to generate the SPV. A manually controlled or automatic servo system maintains a constant predetermined value of the SPV for each wavelength. A drop of a transparent electrolyte solution containing redox couples (preferably quinhydrone) having an oxidation-reduction potential (E) in the order of +0.6 to -1.65 volts couples the SPV to a measurement system. The drop of redox couple solution functions to create a liquid Schottky barrier at the surface of the material. Illumination light is passed through a transparent rod supported over the surface and through the drop of transparent electrolyte. The drop is held in the gap between the rod and the surface. Steady red light is also used as an optical bias to reduce deleterious space-charge effects that occur in amorphous silicon.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- DOE Contract Number:
- EG-77-C-01-4042
- Assignee:
- RCA Corporation (New York, NY)
- Patent Number(s):
- US 4454472
- OSTI ID:
- 865050
- Country of Publication:
- United States
- Language:
- English
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Method and apparatus for determining minority carrier diffusion length in semiconductors
Method and apparatus for determining minority carrier diffusion length in semiconductors
Related Subjects
apparatus
determining
minority
carrier
diffusion
length
semiconductors
provided
carriers
semiconductor
material
particularly
amorphous
silicon
significantly
constant
magnitude
surface-photovoltage
spv
steady
modulated
illumination
wavelengths
provides
light
excitation
surface
generate
manually
controlled
automatic
servo
maintains
predetermined
value
wavelength
drop
transparent
electrolyte
solution
containing
redox
couples
preferably
quinhydrone
oxidation-reduction
potential
-1
65
volts
measurement
couple
functions
create
liquid
schottky
barrier
passed
rod
supported
held
gap
optical
bias
reduce
deleterious
space-charge
effects
occur
carrier diffusion
rod support
diffusion length
schottky barrier
solution containing
amorphous silicon
semiconductor material
electrolyte solution
minority carrier
predetermined value
minority carriers
reduction potential
reduce deleterious
redox couples
automatic servo
manually controlled
particularly amorphous
redox couple
rod supported
modulated illumination
oxidation-reduction potential
determining minority
constant predetermined
light excitation
illumination light
magnitude surface-photovoltage
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