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This content will become publicly available on June 25, 2019

Title: Recombination velocity less than 100 cm/s at polycrystalline Al 2O 3/CdSeTe interfaces

Reducing recombination in polycrystalline solar cells by orders of magnitude is currently one of the greatest challenges for increasing thin-film solar cell efficiency to theoretical limits. The question of how to do this has been a challenge for the thin-film community for decades. This work indicates that effective interface passivation is critical. Here, polycrystalline Al 2O 3/CdSeTe/Al 2O 3/glass heterostructures are grown, and a combination of spectroscopic, microscopic, and time-resolved electro-optical measurements demonstrates that the interface recombination velocity at alumina/thin-film interfaces can be less than 100 cm/s. This is three orders of magnitude less than typical CdTe interfaces without passivation, commensurate with single-crystal epitaxial CdMgSeTe/CdSeTe/CdMgSeTe double heterostructures, and enables minority-carrier lifetimes in polycrystalline CdSeTe well above 100 ns. Microscopic interfacial electric-field measurements identify the field effect as a potential mechanism for polycrystalline Al 2O 3/CdSeTe interface passivation. Furthermore, the results provide guidance for modeling and interface passivation in devices and indicate future paths to realize highly efficient thin-film solar cells.
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [3] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Colorado State Univ., Fort Collins, CO (United States); First Solar, Santa Clara, CA (United States)
  3. Colorado State Univ., Fort Collins, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0003-6951
Grant/Contract Number:
AC36-08GO28308; AC36-08-GO28308; 30306; 30307; EE0007365
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 112; Journal Issue: 26; Journal ID: ISSN 0003-6951
American Institute of Physics (AIP)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; spectroscopy; time resolved spectroscopy; thin films; solar cells; emission spectroscopy; passivation; second harmonic generation; heterojunctions
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1457491