Summer Internship Poster Presentation for UTEP Conferences.

1. TEMPLATE DESIGN © 2008
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• Dissolved Copper (II)
Acetate, Zinc (II)
Acetate, Tin (II) Chloride,
and Sulfur powder in a
mixture solution of
2-methoxyethanol
(solvent) and
monethanolamine
(stabilizer).
• Stirred and heated at
45°C for 1 hour.
• Spin-coated on Soda
Lime Glass (SLG) at
2000rpm, 4000rpm,
6000rpm, 8000rpm,
10000rpm and
12000rpm, respectively. • Repeated for
each sample to
obtain 3-layer
samples.
• Dried at 300°C for
10 min on a hot plate.
• Annealed using MTI
Rapid Thermal
Processing (RTP)
system at 550°C for
60 min.
Ø Raman
Spectroscopy
Ø Scanning Electron
Microscope (SEM)
• Cu2ZnSnS4 (CZTS)
raw materials are
earth-abundant, non-toxic,
and low-cost.
Ø X-Ray Diffraction
(XRD)
Ø Absorption
Spectroscopy
Investigation on the Effects of Spin Speed on the Properties of
Spin-Coated Cu2ZnSnS4 Thin Film
Dwencel John Mamayson1,2, Cheik Sana1, Shaimum Shahriar1, Jose Galindo1, and Deidra Hodges1
1Department of Electrical and Computer Engineering, University of Texas at El Paso, El Paso, TX 79968, USA
2Department of Materials, University of California Santa Barbara, Santa Barbara, CA 93106, USA
Motivation
Methods of Fabrication
Characterization Equipment
Results
Conclusion
Acknowledgement
Ø Absorption Spectroscopy
Ø X-Ray Diffraction (XRD)
Speed
(rpm)
FWHM (2θ°) Crystallite
Size (Å)
d-spacing
(Å)
2000 0.686 118.6 3.12719
4000 0.621 130.9 3.12719
6000 0.512 158.7 3.12719
8000 0.937 86.8 3.12719
10000 0.706 115.2 3.12719
12000 0.726 112.0 3.12719
Ø Scanning Electron Microscope (SEM)
The National Science Foundation (NSF); The University of Texas at El Paso
(UTEP) and The University of California Santa Barbara (UCSB) Partnership
for Research and Education in Materials (PREM) Program [DMR-1205302].
Fig 1. Absorption rates of the CZTS thin-films as a
function of wavelength show the inverse relationship of
absorption rate and spin-speed.
Fig 2. Tauc plots of the CZTS thin-films show their
respective band gaps.
Speed
(rpm)
2000 4000 6000 8000 10000 12000
Band Gap
(eV)
1.10 1.15 1.25 1.13 1.15 1.15
Table 1. Band Gaps of the CZTS Thin-Films
Fig 3. XRD patterns of the CZTS thin-films show the
peaks of the CZTS kesterite structure and secondary
phase.
Table 2. Grain Properties of the CZTS Thin-Films
2000rpm 4000rpm 6000rpm
8000rpm 10000rpm 12000rpm
Fig 4. SEM images of the CZTS thin-films show the
quality of each sample.
Cary 5000 UV-VIS
Spectrophotometer
Bruker D8 Discover
XRD Diffractometer
Hitachi S-4800 SEM
Thermo Scientific DXR
SmartRaman
• The obtained results show that the spin-speed of
6000rpm is preferred for CZTS fabrication.
• However, the samples were divided into two batches,
and each batch was made at different time.
• This has eliminated the possibility of a trend on the
CZTS thin-films’ properties as shown on Table 1,
Table 2, and Fig. 4.
• In addition, Raman spectroscopy is needed to verify
the existence of the secondary and ternary phases
which cannot be shown by the XRD patterns (Fig 3).
Future Works
• Verify the optimum spin-speed for the fabrication of
CZTS thin-film.
• Investigate the effects of varying the reagents’ ratio,
annealing temperature, annealing time, and other
fabrication techniques (such as filtration) to the
properties of CZTS thin-film, respectively.
• CZTS band gaps of
1.0eV to 1.5eV and
optical absorption
coefficient of over
104 cm-1 are suitable for
solar cell application.
References
Hall, D., Underhill, P., & Torkelson, J. (1998). Spin coating of thin and ultrathin
polymer films. Polym. Eng. Sci. Polymer Engineering & Science,
2039-2045.
Yu, Y., Ge, J., Prabhakar, T., & Yan, Y. (2014). Effects of spin speed on the
properties of spin-coated Cu2ZnSnS4 thin films and solar cells based on
DMSO solution. 2014 IEEE 40th Photovoltaic Specialist Conference
(PVSC).
Solvent Stabilizer