By Ackapop Katesomboon Department of Physics Faculty of Science King Mongkut's University of Technology Thonburi.

SURFACE MODIFICATION OF F-DOPED TIN OXIDE THIN FILMS BY WET CHEMICAL ETCHING

ByAckapop Katesomboon

Department of Physics Faculty of Science King Mongkut's University of Technology

Thonburi

Outline

Conclusion2

Introduction

ExperimentResults and Discussion

Introduction

Glass

TCO

amorphous silicon

metal

LIGHT

3

Figure 1. Structure of amorphous silicon solar cell

Introduction (Cont.)

SnCl4(l)+2H2O(l)

SnO2 (S)+4HCl(l)

SnCl4(l)+2H2O(l)

SnO2 (S)+4HCl(l)

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The chemical reaction of SnO2 films coating is

Reverse reaction is

SnO2

Glass

SnO2

SnCl4+2H2OSnO2+4HCl

UV-Vis Spectrophotometer

Atomic Force MicroscopeFour Point

Probes 5

Experiment

Percent transmissio

nrms roughness

Sheet resistance

Experiment (Cont.)

6

Effect of etching concentration / etching time

Effect of etching temperature / etching time

Table 1: Preparation conditions of etching time and HCl concentration at room temperature.Concentration

(%)

Etching time (min)

1, 3, 5 1, 5, 10, 15

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Experiment(Cont.)

Results and Discussion

0 2 4 6 8 10 12 14 1660

62

64

66

68

70

Tra

nspa

rent

(%

)

Etching time (min)

non etching HCl 1% HCl 3% HCl 5%

Fig. 2. The relationship between the percent transmission and the etching times of the specimens etched at different concentration.

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Optical propertie

s

Morphological properties

Results and Discussion

9

HCl 1% 1min

Non etching

Fig 3. 3-D images of spacimensHCl 5% 15min

Etching time

(min)

Con.

(%)

Roughness rms (nm)

Roughness max (nm)

Surfacearea(µm2)

non etched 32.40 225.24 107.021 1 44.20 387.00 121.795 15 40.58 339.95 125.13

Table 2: The roughness of specimen form AFM of relationship between etching concentration and etching time.

Morphological properties

Results and Discussion

10

0 2 4 67.5

8.0

8.5

9.0

9.5

10.0

Sh

eet

resi

stan

ce(

/sq)

concentration (%)

non etching 1min 5min 10min 15min

Electrical properties

Fig. 4. The relationship between the sheet resistance and the concentration of the specimens etched at different of HCl etching times from 1-15 min.

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Results and Discussion

Temperature(oC)

Etching time (min)

40, 45, 50 1, 8, 15

Table 3: Preparation condition to investigate the effect of temperature and etching time at 1% HCl concentration.

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Experiment (Cont.)

Optical properties

34 36 38 40 42 44 46 48 5060

62

64

66

68

70

Tra

nspa

rent

(%

)

Temparature (oC)

non etching 1 min 8 min15 min

Fig. 5. The relationship between the percent transmission and the temperature of the specimens etched at different etching times.

13

Results and Discussion

14

Non etching

50oC 15 min

40oC 1 min

Morphological properties

Fig. 6. 3-D images of spacimen

Results and Discussion

T 

(oC)

Etching time(min)

Roughness rms (nm)

Roughness max (nm)

Surfacearea(µm2)

non etched 32.40 225.24 107.0240 1 44.49 346.28 128.2850 15 44.92 390.89 130.96

Table 4: The roughness of specimen form AFM of relationship between temperature and etching time.

Morphological properties

Results and Discussion

15

38 40 42 44 46 48 507.5

8.0

8.5

9.0

9.5

10.0

Shee

t re

sist

ance

(/s

q)

Temparature (oC)

non etching 1 min 8 min15 min

Fig. 7. The relationship between the sheet resistance and the temperature of the specimens etched at different of etching times from 1-15 min.

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Electrical properties

Results and Discussion

Conclusion

• In the low concentration of etching concentration from 1-5%, the percent transmission, sheet resistance and morphology varied in a small region when changing etching time.• The etching temperature was

not important parameter of this experiment.

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References

[1] N. Senoussaoui, T. Repmann, T. Brammer, H. Stiebig, H. Wangner, Rev. Energ. Ren. 3 (2000) 49-56. [2] N. Amin, T. Isaka, A. Yamada, M. Konagai, Solar Energy Materials & Solar Cells. 67 (2001) 195-201. [3] A. Krasnov, Solar Energy Materials & Solar Cells. 94 (2010) 1648-1657. [4] J. Muller, B. Rech, J. Spinger,M. Vanecek, Solar Energy, 77 (2004) 917-930.[5] A. Fuchs, H- J. Schimper, A. Klein, W. Jaegermann, Energy Procedia, 10 (2011) 149-154.[6]A. Katesomboon,S. Dumrongrattana, T. Lachit, T. Jutarosaga, W. Onreabroy, Physical Propertes of Etching F-Doped Tin Oxide Film for Photovoltaic Application, 38th Congress on Science and Technology of Thailand, Chiangmai, Thailand, (2012), p 162.

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Acknowledgements

Supattanapong Dumrongrattana

Wandee OnreabroyTula Jutarosaga

Department of Physics Faculty of Science

King Mongkut’s University of Technology Thonburi

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