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Title: Method and apparatus for determining minority carrier diffusion length in semiconductors

Abstract

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.

Inventors:
 [1]
  1. Princeton, NJ
Issue Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
OSTI Identifier:
865050
Patent Number(s):
4454472
Assignee:
RCA Corporation (New York, NY)
DOE Contract Number:  
EG-77-C-01-4042
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; 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; /324/136/204/438/

Citation Formats

Moore, Arnold R. Method and apparatus for determining minority carrier diffusion length in semiconductors. United States: N. p., 1984. Web.
Moore, Arnold R. Method and apparatus for determining minority carrier diffusion length in semiconductors. United States.
Moore, Arnold R. Sun . "Method and apparatus for determining minority carrier diffusion length in semiconductors". United States. https://www.osti.gov/servlets/purl/865050.
@article{osti_865050,
title = {Method and apparatus for determining minority carrier diffusion length in semiconductors},
author = {Moore, Arnold R},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1984},
month = {1}
}

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