Determination of effective surface recombination velocity and minority carrier lifetime in high efficiency Si solar cells

Journal Article · Sat Jan 01 04:00:00 EST 1983 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.331693· OSTI ID:7124310

Rose, B H; Weaver, H T

Theoretical analysis and development of a technique were made in order to guarantee measurement of the lifetime of minority charge carriers /tau/ in the base of the mass w and velocity of recombination on the rear surface of the solar cell S in those cases where the diffusion length of the minority carriers of the charge Lgreater than or equal tow. Measurements consists of finding time constants for drop in the photoelectromotive force /tau/v and shortcircuiting current /tau/j with subsequent calculation of /tau/ and S using a computer. The dependence of s on /tau/v and /tau/j is expressed in the form of 1/ j-1/ v = F9S), where F(S) is a transcendental function which is not sensitive to the change in S in the intervals: S<5 x 10/sup 2/ and S>5 x 10/sup 3/ cm/sec. Measurements of the solar cell with specific resistance /rho/ 0.3, 1 and 10 Ohm x cm indicate a rise in /tau/ with increase in /rho/. This agrees qualitatively with the previously published data. After removal of the rear isotype n-n/sup +/-barrier by polishing, S rises from 280 to 4200 cm/sec. In order to verify the reliability and to clarify the area of application of the proposed technique, measurements are made of FP with structure p/sup +/-n-n/sup +/ exposed to subsequent ..gamma..-radiation in doses up to 10/sup 6/ rad. The values of /tau/ which are calculated according to the drop in photoelectromotive force and the shortcircuiting current diminish with radiation from 68 to 1.8 sec. The dose relationship of the coefficient of damage of K is subordinate to the equation 1//tau/ = 1//tau/ /SUB O/ + KF, where F is the radiation dose. The value K equal to 0.5 + and or - 0.1 sec/sup -1/ x rad/sup -1/ agrees with the published data. Parallel calculations of /tau/ according to spectral relationships of photosensitivity of the solar cell result in the corresponding values changing from 15.9 to 0.6 sec. Measurement on the proposed technique of S with an increase in dose to 10/sup 5/ rad rises from 888 to 1762 cm/sec.

• OSTI ID: 7124310
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 54:1; ISSN JAPIA
• Country of Publication: United States
• Language: Russian

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
CARRIER LIFETIME
CHARGE CARRIERS
COMPUTER CALCULATIONS
DIFFUSION LENGTH
DIMENSIONS
DIRECT ENERGY CONVERTERS
DOSIMETRY
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRICAL FAULTS
ELECTRICAL PROPERTIES
ELECTROMOTIVE FORCE
EQUIPMENT
JUNCTIONS
LENGTH
LIFETIME
P-N JUNCTIONS
PHOTOELECTRIC CELLS
PHOTOSENSITIVITY
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLISHING
RADIATION EFFECTS
RECOMBINATION
RELIABILITY
SEMICONDUCTOR JUNCTIONS
SENSITIVITY
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE FINISHING
VELOCITY