The Effect of Na on Cu-K-In-Se Thin Film Growth
| Autor: | Christopher P. Muzzillo, Ho Ming Tong, Timothy J. Anderson |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Diffraction Condensed Matter - Materials Science Photoluminescence Materials science Scanning electron microscope Diffusion Alloy Analytical chemistry Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Inorganic Chemistry Secondary ion mass spectrometry 0103 physical sciences Materials Chemistry engineering Thin film 0210 nano-technology Spectroscopy |
| DOI: | 10.48550/arxiv.1703.06365 |
| Popis: | Co-evaporation of Cu-KF-In-Se was performed on substrates with varied surface Na compositions. Compositions of interest for photovoltaic absorbers were studied, with ratios of (K+Cu)/In ~ 0.85 and K/(K+Cu) ~ 0 - 0.57. Soda-lime glass (SLG) substrates led to the most Na by secondary ion mass spectrometry, while SLG/Mo and SLG/SiO2/Mo substrates led to 3x and 3,000x less Na in the growing film, respectively. Increased Na content favored Cu1-xKxInSe2 (CKIS) alloy formation by X-ray diffraction (XRD), while decreased Na favored the formation of CuInSe2 + KInSe2 mixed-phase films. Scanning electron microscopy and energy dispersive X-ray spectroscopy revealed the KInSe2 precipitates to be readily recognizable planar crystals. Extrinsic KF addition also drove diffusion of Na out from the various substrates and into the growing film, in agreement with previous reports. Time-resolved photoluminescence showed enhanced minority carrier lifetimes for films with moderate K compositions (0.04 < K/(K+Cu) < 0.14) grown on Mo. Due to the relatively high detection limit of KInSe2 by XRD and the low magnitude of chalcopyrite lattice shift for CKIS alloys with these compositions, it is unclear if the lifetime gains were associated with CKIS alloying, minor KInSe2 content, or both. The identified Na-K interdependency can be used to engineer alkali metal bonding in Cu(In,Ga)(Se,S)2 absorbers to optimize both initial and long-term photovoltaic power generation. |
| Databáze: | OpenAIRE |
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