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Methods of Forming CIGS Films

National Renewable Energy Laboratory

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Technology Marketing Summary

Photovoltaic devices that use Cu(In, Ga)Se2 (CIGS) as an absorber layer have improved in recent years, and have the potential to achieve even higher efficiencies. The most common fabrication method produces a CIGS absorber layer with a steep Ga gradient having low levels of Ga at the front of the CIGS absorber layer, which causes a low bandgap and a low open-circuit voltage. These devices also exhibit a poor microstructure with voids, as well as problematic contacts. A fabrication method that homogenizes Ga distribution would enable the creation of higher quality, more efficient CIGS absorber layers.

Description

Researchers at NREL have developed a method of forming a CIGS film using antimony (Sb) that demonstrates improved properties relative to films grown similarly without antimony. When Sb was added during a precursor step prior to selenization, researchers were able to create absorber layers with a homogenous distribution of Ga. The devices fabricated through this process demonstrate increased short circuit current and open circuit voltage as well as enhanced grain size and improved overall efficiency. 

Benefits
  • Higher efficiency CIGS devices
  • Increased short circuit current and open circuit voltage
Applications and Industries
  • CIGS photovoltaics
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 9,768,015
Patent
9,768,015
Methods of forming CIGS films
Methods for forming CIGS films are provided. According to an aspect of the invention, a method of forming a CIGS film includes a precursor step, which includes simultaneously evaporating Cu, In, Ga, Se, and Sb onto a substrate. The Se is incident on the substrate at a rate of at least 20 .ANG./s. The method also includes a selenization step, which includes evaporating Se over the substrate after the precursor step.
National Renewable Energy Laboratory 09/19/2017
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL ROI 15-39PrototypeAvailable09/07/201709/07/2017

Contact NREL About This Technology

To: Bill Hadley<bill.hadley@nrel.gov>