1. 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

2. 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

3. 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)

4. Method of CIS Deposition ● Substrate materials PET & Kapton. ● Electroless Nickel is deposited on substrate ● CIS Deposited on Electroless Nickel (non-recirculated and circulated bath) PET - poly(ethylene terephthalate)

5. AFM Scan Results 50 µm 20 µm 50 µm Annealed CIS Unannealed CIS Unannealed Samples Size: 50 um Roughness: 297 A Grayscale: 400 A Flow rate: 0.72 ml/s Size: 50 um Roughness: 334 A Grayscale: 540 A Flow rate: 0.85 ml/s Annealed Samples Size: 50 um Roughness: 194 A Grayscale: 140 A Flow rate: 0.72 ml/s Size: 50 um Roughness: 206 A Grayscale: 140 A Flow rate: 0.85 ml/s 50 µm

6. 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.

7. XRD scan results

8. Unannealed & Annealed CIS

9. 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.

10. 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.

11. 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.

12. Acknowledgements ● CMU/FAMU PREM Program ● Dr. Salvador and grad students ● Dr. Eric Kalu ● Miss Celina Dozier