Effects of back contact treatments on junction photoluminescence in CdTe/CdS solar cells

Conference · Wed Dec 30 23:00:00 EST 1998

OSTI ID:323665

Levi, D H; Albin, D S; Gessert, T A; Niles, D W; Swartzlander, A; Rose, D H; Ahrenkiel, R K; Sheldon, P ^[1]; Woods, L M ^[2]

---

1. National Renewable Energy Lab., Golden, CO (United States)
2. Colorado State Univ., Ft. Collins, CO (United States)

Device performance in CdTe/CdS solar cells is critically linked to the quality of the back contact. In this paper the authors report on a phenomenon wherein application of the back contact significantly alters the electro-optical properties of the absorber near the junction. They 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.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC36-83CH10093
• OSTI ID: 323665
• Report Number(s): CONF-971201--
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
CADMIUM SULFIDES
CADMIUM TELLURIDE SOLAR CELLS
CADMIUM TELLURIDES
ELECTRIC CONTACTS
ELECTRICAL PROPERTIES
ETCHING
MODIFICATIONS
OPTICAL PROPERTIES
PERFORMANCE
PHOTOLUMINESCENCE