Name: Guogen Liu

Advisor: Prof. Chin

Co-advisor: Prof. Barat

Date: 07/24/2010

XRD and SEM analysis

1. Glass and TCO

2. CdS

CdS is amorphous(XRD) and uneven in surface(SEM)

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

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

Position [°2Theta] (Copper (Cu))

30 40 50 60 70

Counts

0

100

400

900

Solar Cell-5_2

Pos. [°2Th.] Height [cts] FWHM [°2Th.] d-spacing [Å] Rel. Int. [%]23.7457 1287.22 0.0886 3.74713 100.0026.4745 19.54 0.1968 3.36678 1.5233.6422 1.93 0.4723 2.66406 0.1537.7720 32.08 0.1574 2.38174 2.49

Position [°2Theta] (Copper (Cu))

30 40 50 60 70

Counts

0

100

400

900

1600 Solar Cell-4_1

Pos. [°2Th.] Height [cts] FWHM [°2Th.] d-spacing [Å] Rel. Int. [%]23.7248 1749.98 0.0984 3.75039 100.0026.5894 19.53 0.2755 3.35249 1.1233.7510 1.56 0.6298 2.65572 0.0937.7552 28.30 0.1968 2.38276 1.62

g=81.5nm

g=90nm

1. CdTe

CdTe after CdCl2

CdTe before CdCl2

Grain size of the first peak

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

CdCl2 treatment increase CdTe grain size and crystallization

Thank you

?

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: