Local Built-in Potential on Grain Boundary of Cu(In,Ga)Se2 Thin Films

Conference · Fri Dec 31 23:00:00 EST 2004

DOI:https://doi.org/10.1063/1.1737796· OSTI ID:860499

Jiang, C -S; Noufi, R; Ramanathan, K; AbuShama, J A; Moutinho, H R; Al-Jassim, M M

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 the existence 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 photoconversion efficiencies, we conclude that the potential plays a significant role in the device conversion efficiency of NREL's three-stage CIGS device.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO.
• Sponsoring Organization: USDOE
• DOE Contract Number: AC36-99GO10337
• OSTI ID: 860499
• Report Number(s): NREL/CP-520-36981
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
DEVICE
DIRECT MEASUREMENT
DISTRIBUTION
EFFICIENCY
GRAIN BOUNDARIES
GRAIN BOUNDARIES (GBS)
MICROSCOPY
PERFORMANCE
PHOTOCONVERSION
PROBES
PV
SCANNING KELVIN PROBE MICROSCOPY (SKPM)
SOLAR ENERGY
SURFACE POTENTIAL
Solar Energy - Photovoltaics
THIN FILMS
THREE-STAGE
TUNING
WORK FUNCTIONS