Characterization of CuInSe2 Thin Film Solar Cells
Chukwuemeka Shina Aofolaju 1 Advisors: Dr. Eric Egwu Kalu 1 Dr. Paul Salvador 2
By
1. FAMU – FSU College of Engineering
2. Carnegie Mellon University
Research Background
● Cost of Crystalline Silicon versus Fossil fuel electricity generation.
● CIS thin films require less semiconductor material
● They are potentially lighter and thinner than Silicon Solar Cells
● CIS would be relatively inexpensive
CIS – Copper Indium Diselenide
Hypothesis &Experimental Methods
● Hypothesis: CIS deposition conditions influence the CIS film microstructure (atomic composition, film morphology) - affect of electrolyte flow rate
● Experimental Methods● Atomic Force Microscopy
● Views the surface profile of both CIS
● X-ray Diffraction
● Crystal structure and crystal orientation of the thin film particles
● Scanning Electron Microscope (sample atomic composition)
Method of CIS Deposition● Substrate materials PET &
Kapton.
● Electroless Nickel is deposited on substrate
● CIS Deposited on Electroless Nickel (non-recirculated and circulated bath)
Rate (%) Time (s) Volume (ml) Rate (ml/s)40 20.54 10.2 0.550 19.38 12 0.6260 20.38 14.6 0.7270 18.78 16 0.85
PET - poly(ethylene terephthalate)
AFM Scan Results
50 µm 20 µm
50 µm
Annealed CIS
Unannealed CIS Unannealed Samples
Size: 50 umRoughness: 297 AGrayscale: 400 AFlow rate: 0.72 ml/s
Size: 50 umRoughness: 334 AGrayscale: 540 AFlow rate: 0.85 ml/s
Annealed SamplesSize: 50 umRoughness: 194 AGrayscale: 140 AFlow rate: 0.72 ml/s
Size: 50 umRoughness: 206 AGrayscale: 140 AFlow rate: 0.85 ml/s
50 µm
50 µm
X-ray Diffraction
● Understand the molecular and material structure of the thin films
● Monitor peaks and compare them to theoretical CIS scans
● Note the differences or variation in peaks as flow-rate changes.
● Scan annealed samples and see differences in peaks.
XRD scan results
CIS 601B
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Inte
nsity
Unannealed & Annealed CISCIS samples
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nsity
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Result & Discussion
● Peaks are present but are neither at the same angle of the theoretical CIS scans or intensity
● CIS scans are similar to substrate scans (Mylar and Kapton)
● Nickel scans are also similar to that of Mylar and Kapton
● CIS not Crystalline.
SEM Results
● Copper – 19.16 %● Selenium – 41.72 %
● SEM Results show the presence of Copper and Selenium but no Indium. X-ray Diffraction analysis might not be the best way to characterize our samples OR Annealing factors should be changed to show crystalline structures.
Conclusion & Future Goals
● Learned how to use the Atomic Force Microscope to view surface morphology of thin films
● Studied the use of X-ray Diffractormeter and used it to characterize sample
● Change the Annealing factors and find other methods to characterize samples.
● Experiment through more flow rates.