Hostname: page-component-7bb8b95d7b-fmk2r Total loading time: 0 Render date: 2024-09-07T13:39:14.530Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of Back Contact Treatments on Junction Photoluminescence in CdTe/CdS Solar Cells

Published online by Cambridge University Press:  10 February 2011

D. H. Levi ,
L. M. Woods ,
D. S. Albin ,
T. A. Gessert ,
D. W. Niles ,
A. Swartzlander ,
D. H. Rose ,
R. K. Ahrenkiel  and
P. Sheldon
D. H. Levi
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
L. M. Woods
Affiliation:
Colorado State University, Ft. Collins, CO
D. S. Albin
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
T. A. Gessert
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
D. W. Niles
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
A. Swartzlander
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
D. H. Rose
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
R. K. Ahrenkiel
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
P. Sheldon
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 USA
Get access

Abstract

Device performance in CdTe/CdS solar cells is critically linked to the quality of the back contact. In this paper we report on a phenomenon wherein application of the back contact significantly alters the electro-optical properties of the absorber near the junction. We have studied the photoluminescence (PL) spectrum of the near-junction CdTe region in CdTe/CdS solar cells before and after contact application. It is found that the elemental Tellurium layer formed on the CdTe surface by the standard nitric-phosphoric etch process results in a dramatic qualitative change in the junction PL spectrum. Prior to NP etch, the spectrum has two peaks at energies of 1.50 eV and 1.45 eV, corresponding to recombination in bulk CdTe, and in a CdTeS alloy with 9% sulfur content, respectively. After NP etch, the relative intensity of the low-energy peak is reduced, and the peak shifts towards higher energy. These changes are consistent with a model of increased band-bending at the grain boundaries near the CdTe/CdS heterojunction.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 485: Symposium G – Thin Film Structures for Photovoltaics , 1997 , 209
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Tyan, Y.S., U.S. Patent 4,319,069 (March 9, 1982).Google Scholar
[2] Li, X., Niles, D.W., Hasoon, F.S., Matson, R.J., and Sheldon, P., to be published.Google Scholar
[3] The calculated densities assume a carrier lifetime of 500 ps.Google Scholar
[4] Levi, D.H., et.al,Proc. 24th IEEE Photovoltaic Spec. Conf, 1994, pp. 127–131.Google Scholar
[5] CdTeS alloy composition vs. bandgap is calculated from recent results, personal conversation, Albin, D..Google Scholar
[6] Niles, D.W., Li, X., Sheldon, P., and Hochst, H., Journal Of Applied Physics, 77(9), 1995, p. 4489.Google Scholar
[7]Vol.17, Landoldt-Bomstein New Series, Numerical Data and Functional Relationships in Science and Technology, edited by Hellwege, K.-H. (Springer, Berlin, 1983), pp. 106–117.Google Scholar
[8] Fahrenbruch, A.L., Bube, R.H., Fundamentals of Solar Cells, (Academic Press, New York, New York, 1983), p. 387 & ff.Google Scholar
[9] Brian McCandless, E. and Birkmire, Robert W., Solar Cells, 31, 1991, pp. 527.Google Scholar
[10] Jassim, Mowafak A, personal communication, Sept, 1997.Google Scholar