Effect of Na Incorporation on the Growth and Properties of CdTe/CdS Devices OF CdTe/CdS DEVICES
Sodium is known to enhance p-type doping in copper indium diselenide (CIS)-based devices fabricated on soda-lime glass substrates, and similar amounts of Na are present in commercial cadmium telluride (CdTe) devices. We present the results on the effects of Na incorporation on the properties of CdTe/CdS solar cells prepared on borosilicate glass substrates. A NaF layer 10 to 30 nm thick was incorporated at either the CdS/CdTe interface or on the CdTe surface, as a source of Na. CdTe layers were deposited by close-spaced sublimation at substrate temperatures from 425 C (LT) to 620 C (HT), followed by heat-treatment in the presence of CdCl2 vapor. Atomic force microscopy analysis showed that the samples with NaF at the CdS/CdTe interface deposited in He ambient have larger grains with a sub-grain structure that disappears after CdCl2 heat treatment accompanied by an increase in grain size. Samples deposited in O2 ambient have smaller grains without a sub-grain structure. For samples with NaF deposited on the CdTe surface, LT samples with CdCl2 heat treatment showed a morphology similar to samples without NaF layers; but samples heat-treated in He ambient at 500 C prior to CdCl2 treatment showed a different microstructure with platelets on the surface.
- Research Organization:
- National Renewable Energy Lab., Golden, CO (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC36-99-GO10337
- OSTI ID:
- 15016401
- Report Number(s):
- NREL/CP-520-37368; TRN: US200513%%378
- Resource Relation:
- Conference: Prepared for the 31st IEEE Photovoltaics Specialists Conference and Exhibition, Lake Buena Vista, FL (US), 01/03/2005--01/07/2005; Other Information: PBD: 1 Feb 2005
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
BOROSILICATE GLASS
CADMIUM TELLURIDES
COPPER
GLASS
GRAIN SIZE
HEAT TREATMENTS
INDIUM
MICROSTRUCTURE
MORPHOLOGY
SODIUM
SOLAR CELLS
SUBLIMATION
SUBSTRATES
PV
P-TYPE DOPING
COPPER INDIUM DISELENIDE (CIS)
DEVICES
SODA-LIME GLASS SUBSTRATES
CADMIUM TELLURIDE (CDTE)
SOLAR ENERGY - PHOTOVOLTAICS