skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Reduced defect density at the CZTSSe/CdS interface by atomic layer deposition of Al{sub 2}O{sub 3}

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.4948947· OSTI ID:22596992
 [1];  [2]
  1. Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)
  2. AQT Solar, Inc., Sunnyvale, California 94086 (United States)

The greatest challenge for improving the power conversion efficiency of Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe)/CdS/ZnO thin film solar cells is increasing the open circuit voltage (V{sub OC}). Probable leading causes of the V{sub OC} deficit in state-of-the-art CZTSSe devices have been identified as bulk recombination, band tails, and the intertwined effects of CZTSSe/CdS band offset, interface defects, and interface recombination. In this work, we demonstrate the modification of the CZTSSe absorber/CdS buffer interface following the deposition of 1 nm-thick Al{sub 2}O{sub 3} layers by atomic layer deposition (ALD) near room temperature. Capacitance-voltage profiling and quantum efficiency measurements reveal that ALD-Al{sub 2}O{sub 3} interface modification reduces the density of acceptor-like states at the heterojunction resulting in reduced interface recombination and wider depletion width. Indications of increased V{sub OC} resulting from the modification of the heterojunction interface as a result of ALD-Al{sub 2}O{sub 3} treatment are presented. These results, while not conclusive for application to state-of-the-art high efficiency CZTSSe devices, suggest the need for further studies as it is probable that interface recombination contributes to reduced V{sub OC} even in such devices.

OSTI ID:
22596992
Journal Information:
Journal of Applied Physics, Vol. 119, Issue 19; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
Country of Publication:
United States
Language:
English

Cited By (5)

Trap density simulations on CZTSSe solar cells with AMPS-1D journal April 2018
Improved quantum efficiency models of CZTSe: GE nanolayer solar cells with a linear electric field journal January 2018
Enhanced efficiency of Cu 2 ZnSn(S,Se) 4 solar cells via anti-reflectance properties and surface passivation by atomic layer deposited aluminum oxide journal January 2018
Cd-Free Cu 2 ZnSnS 4 solar cell with an efficiency greater than 10% enabled by Al 2 O 3 passivation layers journal January 2019
An efficient analytical model for tandem solar cells journal April 2019