Hall-effect Characterization and Identification of Impurity Levels in Multi-Crystalline Silicon Base Material for Solar Cells

  • David M Mulati Department of Physics, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000, Nairobi
  • Hiroyuki Matsunami Department of electronic Science and Engineering, Kyoto University, Sakyo 606-8501 Japan
Keywords: Compensation, multi-crystalline silicon, activation energy, mobility, grain boundaries

Abstract

Samples of 1cm2 sizes were made from the p-type multi-crystalline silicon boron doped 1016cm-3. Aluminium contacts were made in a vacuum of 10-6 Torr and post-annealed in Argon ambient at 400°C for 30 minutes for making the four contact electrodes. The activation energy based on low compensation was found to be 47 meV, 32 meV, and 18 meV, respectively. In order to obtain a more reliable solution, the differential evaluation on the temperature dependence of hole concentration was done. Four peaks were observed around 50, 56, 88, and 109 meV, which indicate several acceptor levels in multi-crystalline silicon (Mx-Si). Hall mobility at 300 K in this p-type sample was 189 (cm2/Vs) and 3231 (cm2/Vs) at 72 K. Based on acoustic phonon scattering the mobility decrease with temperature showed T-1.96 dependence. This behavior indicates the inter-valley scattering as well as grain boundary effects.

KEY WORDS: Compensation, multi-crystalline silicon, activation energy, mobility, grain boundaries

J. agric. Sci. technol. Vol.5(1) 2003: 106-115
Published
2004-11-15
Section
Articles

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eISSN: 1561-7645