Hostname: page-component-76fb5796d-dfsvx Total loading time: 0 Render date: 2024-04-26T07:33:24.122Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of c-Si1-xGex Thickness Grown by LPCVD on the Performance of Thin-Film a-Si/c-Si1-xGex/c-Si Heterojunction Solar Cells

Published online by Cambridge University Press:  13 June 2012

Sabina Abdul Hadi ,
Pouya Hashemi ,
Nicole DiLello ,
Ammar Nayfeh  and
Judy L. Hoyt
Sabina Abdul Hadi
Affiliation:
Microsystems Engineering, Masdar Institute of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
Pouya Hashemi
Affiliation:
Microsystems Technology Laboratories, MIT, Cambridge, MA 02139, USA
Nicole DiLello
Affiliation:
Microsystems Technology Laboratories, MIT, Cambridge, MA 02139, USA
Ammar Nayfeh
Affiliation:
Microsystems Engineering, Masdar Institute of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
Judy L. Hoyt
Affiliation:
Microsystems Technology Laboratories, MIT, Cambridge, MA 02139, USA
Get access

Abstract

In this paper the effect of Si1-xGex absorber layer thickness on thin film a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) is studied by simulation and experiment. Cells with 1, 2 and 4 μm-thick epitaxial cap layers of p-type Si0.59Ge0.41 on top of 5 μm Si1-xGex graded buffer layers are fabricated and compared to study the effect of the absorber layer thickness. The results show no change in Voc (0.41V) and that Jsc increases from 17.2 to 18.1 mA/cm2 when the Si0.59Ge0.41 absorber layer thickness is increased from 1 to 4 μm. The effect of thickness on Jsc is also observed for 2 and 4 μm-thick Si and Si0.75Ge0.25 absorber layers. Experiments and simulations show that larger Ge fractions result in a higher magnitude and smaller thickness dependence of Jsc, due to the larger absorption coefficient that increases optical carrier generation in the near surface region for larger Ge contents.

Keywords

Gechemical vapor deposition (CVD) (deposition)photovoltaic
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1447: Symposium V – Nanostructured and Advanced Materials for Solar-Cell Manufacturing , 2012 , mrss12-1447-v01-09
Copyright
Copyright © Materials Research Society 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Beaucarne, G., Duerinckx, F., Kuzma, I., Nieuwenhuysen, K.V., Kim, H.J. and Portmans, J. “Epitaxial thin-film Si solar cells,” Thin Solid Films, vol. 511–512, pp. 533–542, July 2006.Google Scholar
2. Said, K., et al. , “Design, Fabrication, and Analysis of Crystalline Si-SiGe Heterostructure Thin-Film Solar Cells,” IEEE Transactions On Electron Device, vol. 46, no. 10, pp. 2103–2110, Oct 1999.Google Scholar
3. Taguchi, M., et al. , “HIT Cells – High-Efficiency Crystalline Si Cells with Novel Structures,” Progress in Photovoltaics: Research and Applications, vol. 8, pp. 503–513, Sep/Oct 2000.Google Scholar
4. Alberi, K., et al. , “Material quality requirements for efficient epitaxial film silicon solar cells,” Appl. Phys. Lett., vol. 96, pp.073502-0732502-3, Feb 2010.Google Scholar
5. Abdul Hadi, S., Hashemi, P., Nayfeh, A., Hoyt, J., “a-Si/c-Si1-xGex/c-Si Heterojunction Solar Cells,” in Procedding of the IEEE International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), Sep. 2011.Google Scholar
6. Abdul Hadia, S., Hashemi, P., Nayfeh, A., and Hoyt, J. L., “Thin-Film a-Si/c-Si1-xGex/c-Si Heterojunction Solar Cells: Design and Material Quality Requirements,” in Proceeding Electrochem. Society, 2011.Google Scholar
7. TCAD: Process and device Simulation Tools, World Wide Web: http://www.synopsys.com/Tools/TCAD/Pages/default.aspx Google Scholar
8. Sopra Semilab “n-k Database”, World Wide Web: http://www.sopra-sa.com Google Scholar
9. Kasper, E. (1995). Properties of Strained and Relaxed SiGe. London: Institution of Electrical Engineers.Google Scholar
10. Braunstein, R. Moore, A. R., and Herman, F. “Instrinsic Optical Absoprtion of Germanium-Silicon Alloys,” Phys. Rev., vol. 109, pp. 695–710, 1963.Google Scholar
11. Kleider, J.P., Gudovskikh, A.S., Cabarrocas, P.,“Determination of the conduction band offset between hydrogenated amorphous silicon and crystalline silicon from surface inversion layer conductance measurements,” Appl. Phys. Lett., vol. 92, pp.162101 (2008).Google Scholar
12. Fossum, J. G. and Lee, D. S., “A Physical Model for the Dependence of Carrier Lifetime on Doping Density in Nondegenerate Silicon,” Solid-State Electronics, vol. 25, no. 8, pp. 741–747, 1982.Google Scholar
13. I. Aberg, Ph.D. Thesis, MIT, 2006.Google Scholar
14. ITO/a-Si deposited by MVSystems, Inc.Google Scholar