AFM-Based Microelectrical Characterization of Grain Boundaries in Cu(In,Ga)Se2 Thin Films

Research output: Contribution to conferencePaper

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 languageAmerican English
Number of pages7
StatePublished - 2005
Event31st IEEE Photovoltaics Specialists Conference and Exhibition - Lake Buena Vista, Florida
Duration: 3 Jan 20057 Jan 2005

Conference

Conference31st IEEE Photovoltaics Specialists Conference and Exhibition
CityLake Buena Vista, Florida
Period3/01/057/01/05

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)

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