Back contact effects on junction photoluminescence in CdTe/CdS solar cells

Author

Levi, D.H. ; Woods, L.M. ; Albin, D.S. ; Gessert, T.A. ; Niles, D.W. ; Swartziender, A. ; Rose, D.H. ; Ahrenkiel, R.K. ; Sheldon, P.

Author_Institution

Nat. Renewable Energy Lab., Golden, CO, USA

fYear

1997

fDate

29 Sep-3 Oct 1997

Firstpage

351

Lastpage

354

Abstract

Studies of junction photoluminescence in CdTe/CdS solar cells reveal that back-contact application produces a dramatic qualitative change in the junction PL spectrum. Prior to contact application, the spectrum has two peaks at energies of 1.508 eV and 1.45 eV, corresponding to recombination in bulk CdTe, and in a CdTeS alloy with 9% sulfur content, respectively. After contact application, the spectrum consists of a single broad peak at 1.48 eV. Previous studies have shown that the nitric-phosphoric (NP) etch used in the contact procedure produces a layer of elemental Tellurium (Te) on the CdTe surface. The authors´ measurements utilizing Auger electron spectroscopy (AES) show that this Te layer penetrates grain boundaries down to the CdTe/CdS interface. It appears that the change in the near-junction PL spectrum is caused by a “grain boundary field effect” due to perturbations of the grain boundary conductivity and Fermi level

Keywords

Auger effect; II-VI semiconductors; cadmium compounds; electron spectroscopy; p-n heterojunctions; photoluminescence; semiconductor device testing; solar cells; 1.45 eV; 1.48 eV; 1.508 eV; Auger electron spectroscopy; CdTe-CdS; CdTe/CdS solar cells; Fermi level; back contact effects; contact application; grain boundaries; junction photoluminescence; measurements; perturbations; recombination; Charge carrier density; Density measurement; Etching; Grain boundaries; Photoluminescence; Photovoltaic cells; Pulse measurements; Surface treatment; Tellurium; Wavelength measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE

Conference_Location

Anaheim, CA

ISSN

0160-8371

Print_ISBN

0-7803-3767-0

Type

conf

DOI

10.1109/PVSC.1997.654100

Filename

654100