Abstract
We report on a direct measurement of two-dimensional potential distribution on the surface of Cu(In,Ga)Se2 thin films using a nanoscale electrical characterization of scanning Kelvin probe microscopy both in air and in ultra-high vacuum. 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. Thisdemonstrates the existence of a local built-in potential on GBs, and the GB is positively charged. The role of the built-in potential in device performance was further examined and found to be positive, by tuning Ga content or bandgap of the film. With increasing Ga content, the potential drops sharply in a Ga range of 28%~38%. Comparing the change in the built-in potential to the theoreticaland experimental photoconversion efficiencies, we conclude that the potential plays a significant role in the device conversion efficiency of NREL's three-stage Cu(In,Ga)Se2 device.
| Original language | American English |
|---|---|
| Number of pages | 7 |
| State | Published - 2005 |
| Event | 31st IEEE Photovoltaics Specialists Conference and Exhibition - Lake Buena Vista, Florida Duration: 3 Jan 2005 → 7 Jan 2005 |
Conference
| Conference | 31st IEEE Photovoltaics Specialists Conference and Exhibition |
|---|---|
| City | Lake Buena Vista, Florida |
| Period | 3/01/05 → 7/01/05 |
NREL Publication Number
- NREL/CP-520-37338
Keywords
- AFM-based microelectrical characterization
- device conversion efficiency
- grain boundaries (GBS)
- nanoscale electrical characterization
- PV
- scanning Kelvin probe microscopy (SKPM)