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Title: Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

Authors:
 [1];  [2];  [3];  [3];  [2];  [2];  [2];  [4];  [4];  [5]
  1. Indian Institute of Technology Bombay, Powai Mumbai 400076 India, Sanjivani College of Engineering, Kopargaon 423601 India
  2. Indian Institute of Technology Bombay, Powai Mumbai 400076 India
  3. MoserBaer Photovoltaic Pvt. Ltd., U.P. Greater Noida 201306 India
  4. National Renewable Energy Laboratory, Golden CO 80401 USA
  5. Indian Institute of Technology Bombay, Powai Mumbai 400076 India, Indian Institute of Technology Goa, Farmagudi Ponda 403401 India
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1408251
Grant/Contract Number:
AC36-08GO28308; IUSSTF/JCERDCSERIIUS/2012
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physica Status Solidi. A, Applications and Materials Science
Additional Journal Information:
Journal Volume: 215; Journal Issue: 2; Related Information: CHORUS Timestamp: 2018-01-25 05:17:50; Journal ID: ISSN 1862-6300
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
Germany
Language:
English

Citation Formats

Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., van Hest, Maikel F. A. M., and Arora, Brij M. Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique. Germany: N. p., 2017. Web. doi:10.1002/pssa.201700267.
Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., van Hest, Maikel F. A. M., & Arora, Brij M. Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique. Germany. doi:10.1002/pssa.201700267.
Khatavkar, Sanchit, Muniappan, Kulasekaran, Kannan, Chinna V., Kumar, Vijay, Narsimhan, Krishnamachari L., Nair, Pradeep R., Vasi, Juzer M., Contreras, Miguel A., van Hest, Maikel F. A. M., and Arora, Brij M. 2017. "Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique". Germany. doi:10.1002/pssa.201700267.
@article{osti_1408251,
title = {Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique},
author = {Khatavkar, Sanchit and Muniappan, Kulasekaran and Kannan, Chinna V. and Kumar, Vijay and Narsimhan, Krishnamachari L. and Nair, Pradeep R. and Vasi, Juzer M. and Contreras, Miguel A. and van Hest, Maikel F. A. M. and Arora, Brij M.},
abstractNote = {},
doi = {10.1002/pssa.201700267},
journal = {Physica Status Solidi. A, Applications and Materials Science},
number = 2,
volume = 215,
place = {Germany},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on November 10, 2018
Publisher's Accepted Manuscript

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  • A three-dimensional transient model for time-domain (modulated) free-carrier absorption (FCA) measurement was developed to describe the transport dynamics of photo-generated excess carriers in silicon (Si) wafers. With the developed transient model, numerical simulations were performed to investigate the dependences of the waveforms of the transient FCA signals on the electronic transport parameters of Si wafers and the geometric parameters of the FCA experiment. Experimental waveforms of FCA signals of both n- and p-type Si wafers with resistivity ranging 1–38 Ω·cm were then fitted to the three-dimensional transient model to extract simultaneously and unambiguously the transport parameters of Si wafers, namely,more » the carrier lifetime, the carrier diffusion coefficient, and the front surface recombination velocity via multi-parameter fitting. A basic agreement between the extracted parameter values and the literature values was obtained.« less
  • An expression for the collection velocity S of excess minority carriers at metal-semiconductor contacts is derived analytically for both the Schottky barrier and the Ohmic contact. Short-circuit conditions are assumed, appropriate to the collection of optically generated minority carriers by Schottky barriers or Ohmic contacts in solar cells or photodetectors. This analysis is then applied to the calculation of S for the materials of primary interest in solar cells (Si, GaAs, and CdS). It is found that S increases with the minority-carrier mobility and with the doping concentration according to Sapprox...mu../sub p/ N/sup 1///sup 2//sub d/ (for the contact: metal--n-typemore » semiconductor), but is independent of the barrier height phi/sub b/ or diffusion potential V/sub d//sub o/, provided qV/sub d//sub o/approximately-greater-than few KT. This means that, for Ohmic contacts, S depends on whether the contact is achieved by using high N/sub d/ (for which Sapprox. =10/sup 9/ cm/s for Si cells) or by low phi/sub b/ but moderate N/sub d/ (Sapprox. =10/sup 7/ cm/s for Si cells). More generally, S varies between approx. =10/sup 6/ cm/s (for CdS cells, low N/sub d/) and approx. =10/sup 10/ cm/s (p-type GaAs cells, high N/sub d/). Also defined are the conditions under which the finite collection velocity at the contact limits the collected minority-carrier current. (AIP)« less
  • The method for measuring the recombination rate by modulation of the impurity photoconductivity is described. It is shown that this method can be used for the determination, at different temperatures, of the cross sections for capture of majority carriers by impurities with deep levels. (auth)
  • The role of Ga in CIGS solar cells is complex. In addition to its primary role of alloying agent to increase the band gap we also observe its influence on passivation, transport, trapping and doping. At low levels it can positively influence all of these mechanisms and improve performance. As its level is increased, there are complex tradeoffs among these that must be controlled to maintain good performance. We have applied photocapacitance techniques to study the junction interface region and the role that Ga plays in its formation and operation. We observe a correlation between the defect that provides dopingmore » and the recombination centers, which control Voc. The dominant centers are deep in the band gap and are located near the metallurgical junction. It is proposed that a reduction of the correlated doping defect will result in improved interface properties. {copyright} {ital 1999 American Institute of Physics.}« less