1. Name: Guogen Liu Advisor: Prof. Chin Co-advisor: Prof. Barat Date: 07/24/2010 XRD and SEM analysis

2. 1. Glass and TCO

3. 2. CdS CdS is amorphous(XRD) and uneven in surface(SEM)

4. Both CdS layers (CBD or Sputtering) are amorphous(XRD) CdCl2 treatment didn’t result in crystallization There are lots of impurities on the surface which result in uneven

5. From the XRD of one peak, we can make sure CdS layer is amorphous

6. Pos. [°2Th.]Height [cts]FWHM [°2Th.]d-spacing [Å]Rel. Int. [%] 23.74571287.220.08863.74713100.00 26.474519.540.19683.366781.52 33.64221.930.47232.664060.15 37.772032.080.15742.381742.49 Pos. [°2Th.]Height [cts]FWHM [°2Th.]d-spacing [Å]Rel. Int. [%] 23.72481749.980.09843.75039100.00 26.589419.530.27553.352491.12 33.75101.560.62982.655720.09 37.755228.300.19682.382761.62 g=81.5nm g=90nm 1. CdTe CdTe after CdCl2 CdTe before CdCl2 Grain size of the first peak

7. The CdTe grain size is very small, less than 100nm. After CdCl2 treatment, it increases a little.

8. CdCl2 treatment increase CdTe grain size and crystallization

9. Thank you ?

10. a, TCO surface should be clean completely b, Add a thin resistivity buffer layer between TCO and CdS c, CdS is not uniform and too much defect after CdCl2 treatment d, the grain size of CdTe is too small, close to amorphous d, Oxygen is necessary in the growth of CdTe crystal e, Vapor CdCl2 treatment is very important f, It is better to increase CdTe deposition temperture g, back contact and Cu doping can affect efficiency greatly h, Pay more attention on the interface between each layer i, try to convert thermal evaporation to CSS which is much mature j, try to do each step successfully first, then step by step Conclusion: