CdS and Cd-Free Buffer Layers on Solution Phase Grown Cu2ZnSn(SxSe1- x)4 :Band Alignments and Electronic Structure Determined with Femtosecond Ultraviolet Photoemission Spectroscopy
The heterojunctions formed between solution phase grown Cu2ZnSn(SxSe1- x)4(CZTS,Se) and a number of important buffer materials including CdS, ZnS, ZnO, and In2S3, were studied using femtosecond ultraviolet photoemission spectroscopy (fs-UPS) and photovoltage spectroscopy. With this approach we extract the magnitude and direction of the CZTS,Se band bending, locate the Fermi level within the band gaps of absorber and buffer and measure the absorber/buffer band offsets under flatband conditions. We will also discuss two-color pump/probe experiments in which the band bending in the buffer layer can be independently determined. Finally, studies of the bare CZTS,Se surface will be discussed including our observation of mid-gap Fermi level pinning and its relation to Voc limitations and bulk defects.
- Publication Date:
- OSTI Identifier:
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- Resource Relation:
- Journal Name: MRS Proceedings / Volume 1638 / 2014; Journal Volume: 1638; Conference: Materials Research Society (MRS) Fall Meeting 2013 Boston, MA Dec. 2-6, 2013
- Research Org:
- IBM TJ Watson Research Center
- Sponsoring Org:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Country of Publication:
- United States
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