Abstract
We report on a direct measurement of two-dimensional potential distribution on the surface of Cu(In,Ga)Se2 (CIGS) thin films using a nanoscale electrical characterization of scanning Kelvin probe microscopy (SKPM). The potential measurement reveals a higher surface potential or a smaller work function on grain boundaries (GBs) of the film than on the grain surfaces. This demonstrates theexistence of a local built-in potential on GBs and that the GB is positively charged. The role of the built-in potential in device performance was further examined by tuning Ga content or band gap of the film. With increasing Ga content, the GB potential drops sharply in a Ga range of 28%~38%. Comparing the change in the built-in potential to the theoretical and experimental photoconversionefficiencies, we conclude that the potential plays a significant role in the device conversion efficiency of NREL's three-stage CIGS device.
Original language | American English |
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Number of pages | 5 |
State | Published - 2005 |
Event | 2004 DOE Solar Energy Technologies Program Review Meeting - Denver, Colorado Duration: 25 Oct 2004 → 28 Oct 2004 |
Conference
Conference | 2004 DOE Solar Energy Technologies Program Review Meeting |
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City | Denver, Colorado |
Period | 25/10/04 → 28/10/04 |
Bibliographical note
Presented at the 2004 DOE Solar Energy Technologies Program Review Meeting, 25-28 October 2004, Denver, Colorado. Also included in the proceedings available on CD-ROM (DOE/GO-102005-2067; NREL/CD-520-37140)NREL Publication Number
- NREL/CP-520-36981
Keywords
- devices
- direct measurement
- grain boundaries (GBS)
- photoconversion
- PV
- scanning Kelvin probe microscopy (SKPM)
- thin films
- three-stage