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Title: Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe

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Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Journal of Photovoltaics; Journal Volume: 5; Journal Issue: 1, January 2015
Country of Publication:
United States

Citation Formats

Kuciauskas, D., Kanevce, A., Dippo, P., Seyedmohammadi, S., and Malik, R. Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe. United States: N. p., 2015. Web. doi:10.1109/JPHOTOV.2014.2359738.
Kuciauskas, D., Kanevce, A., Dippo, P., Seyedmohammadi, S., & Malik, R. Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe. United States. doi:10.1109/JPHOTOV.2014.2359738.
Kuciauskas, D., Kanevce, A., Dippo, P., Seyedmohammadi, S., and Malik, R. 2015. "Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe". United States. doi:10.1109/JPHOTOV.2014.2359738.
title = {Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe},
author = {Kuciauskas, D. and Kanevce, A. and Dippo, P. and Seyedmohammadi, S. and Malik, R.},
abstractNote = {},
doi = {10.1109/JPHOTOV.2014.2359738},
journal = {IEEE Journal of Photovoltaics},
number = 1, January 2015,
volume = 5,
place = {United States},
year = 2015,
month = 1
  • A mathematical analysis for minority-carrier diffusion in a solar cell base is used to extract bulk lifetime tau and effective back-surface recombination velocity S from measurements of asymptotic decay times of short-circuit current and open-circuit voltage. Since the decay times depend individually on both S and tau, it is necessary to use both current and voltage data for unique results. Experimental measurements of current and voltage transients are presented from variable base resistivity cells, ..gamma..-irradiated cells, and cells with intentionally damaged back-surface field regions. Lifetimes determined in these experiments are compared with conventional techniques. The results show that these conventionalmore » techniques yield lifetimes in serious error for cells whose diffusion lengths approach base thickness.« less
  • 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 themore » 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.« less
  • The bulk Shockley-Read-Hall carrier lifetime of CdTe and interface recombination velocity at the CdTe/Mg{sub 0.24}Cd{sub 0.76}Te heterointerface are estimated to be around 0.5 μs and (4.7 ± 0.4) × 10{sup 2 }cm/s, respectively, using time-resolved photoluminescence (PL) measurements. Four CdTe/MgCdTe double heterostructures (DHs) with varying CdTe layer thicknesses were grown on nearly lattice-matched InSb (001) substrates using molecular beam epitaxy. The longest lifetime of 179 ns is observed in the DH with a 2 μm thick CdTe layer. It is also shown that the photon recycling effect has a strong influence on the bulk radiative lifetime, and the reabsorption process affects the measured PL spectrum shape and intensity.
  • Minority carrier lifetime is an efficient indicator of defect levels present in the starting material as well as process and equipment induced defects. By employing rapid thermal processing (RTP) and rapid photothermal processing (RPP) as the thermal processing techniques, the authors have studied the effect of ultraviolet (UV) and vacuum ultraviolet (VUV) photons on the bulk minority carrier lifetime of phosphorus doped and undoped single crystal silicon wafers. For both diffused and undiffused wafers, the authors have observed an enhancement in the minority carrier lifetime when UV and VUV photons are used in conjunction with the samples processed without themore » use of UV and VUV photons. The effect of ramp rates on the minority carrier lifetime and the significance of optimized thermal cycles have also been studied in this paper. A possible explanation based on the dependence of diffusion coefficient on the photo spectrum of light source is also given in this paper.« less