Abstract
We observed photoexcited carrier responses in solar cells excited by femtosecond laser pulses with spatial and temporal resolution using an optical pump-terahertz emission probe technique. We visualized the ultrafast local variation of the intensity of terahertz emission from a polycrystalline silicon solar cell using this technique and clearly observed the change in signals between a grain boundary and the inside of a grain in the solar cell. Further, the time evolution of the pump–probe signals of the polycrystalline and monocrystalline silicon solar cells was observed, and the relaxation times of photoexcited carriers in the emitter layers of crystalline silicon solar cells were estimated using this technique. The estimated relaxation time was consistent with the lifetime of the Auger recombination process that was dominant in heavily doped silicon used as an emitter layer for the silicon solar cells, which is difficult to obtain with photoluminescence method commonly used for the evaluation of solar cells.
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References
M. Tonouchi, “Cutting-edge terahertz technology,” Nat. Photonics, 1, 97 (2007).
K. E Peiponen, J. A. Zeitler, M. K. Gonokami, Terahertz Spectroscopy and Imaging, (Springer, Berlin, 2013) pp. 506.
K. Kawase, Y. Ogawa, and Y. Watanabe, “Non-destructive terahertz imaging of illicit drugs using spectral fingerprints,” Opt. Express, 11, 2549 (2003).
S. Koenig, D. Lopez-Diaz, J. Antes, F. Boes, R. Henneberger, A. Leuther, A. Tessmann, R. Schmogrow, D. Hillerkuss, R. Palmer, T. Zwick, C. Koos, W. Freude, O. Ambacher, J. Leuthold, I. Kallfass, “Wireless sub-THz communication system with high data rate,” Nat. Photonics, 7, 977 (2013).
T. Kiwa, M. Tonouchi, M. Yamashita, K. Kawase, “Laser terahertz-emission microscope for inspecting electrical faults in integrated circuits,” Opt. Lett., 28, 2058 (2003).
M. Tonouchi, N. Uchida, S. Kim, R. Inoue, H. Murakami, “Laser terahertz emission microscope,” Terahertz Sci. Technol., 1, 28 (2008).
M. Yamashita, C. Otani, K. Kawase, K. Nikawa, M. Tonouchi, “Noncontact inspection technique for electrical failures in semiconductor devices using a laser terahertz emission microscope,” Appl. Phys. Lett., 93, 041117 (2008).
Y. Jin, X. F. Ma, G. A. Wagoner, M. Alexander, X. C. Zhang, “Anomalous optically generated THz beams from metal/GaAs interfaces,” Appl. Phys. Lett., 65, 682 (1994).
H. Nakanishi, S. Fujiwara, K. Takayama, I. Kawayama, H. Murakami, M. Tonouchi, “Imaging of a polycrystalline silicon solar cell using a laser terahertz emission microscope,” Appl. Phys. Express, 5, 112301 (2012).
K. A. Salek, H. Nakanishi, A. Ito, I. Kawayama, H. Murakami, M. Tonouchi, “Laser terahertz emission microscopy studies of a polysilicon solar cell under the illumination of continuous laser light,” Optical Engineering, 53 (3), 031204 (2014).
H. Nakanishi, A. Ito, K. Takayama, I. Kawayama, H. Murakami, M. Tonouchi, “Comparison between laser terahertz emission microscope and conventional methods for analysis of polycrystalline silicon solar cell,” AIP Advances, 5, 117129 (2015).
M. A. Green, “Third generation photovoltaics: solar cells for 2020 and beyond,” Physica E, 14, 65 (2002).
G. Conibeer, “Third-generation photovoltaics,” Mater. Today, 10, 42 (2007).
M. C. Beard, “Multiple exciton generation in semiconductor quantum dots,” J. Phys. Chem. Lett., 2, 1282 (2011).
Q. Shen, K. Katayama, T. Sawada, S. Hachiya, T. Toyoda, “Ultrafast carrier dynamics in PbS quantum dots,” Chem. Phys. Lett., 542, 89 (2012).
M. Tonouchi, N. Kawasaki, T. Yoshimura, H. Wald, P. Seidel, “Pump and Probe Terahertz Generation Study of Ultrafast Carrier Dynamics in Low-Temperature Grown-GaAs,” Jpn. J. Appl. Phys., 41, 706 (2002).
H. Murakami, K. Serita, Y. Maekawa, S. Fujiwara, E. Matsuda, S. Kim, I. Kawayama, M. Tonouchi, “Scanning laser THz imaging system,” J. Phys. D: Appl. Phys., 47, 374007 (2014).
A. J. Sabbah, D. M. Riffe, “Femtosecond pump-probe reflectivity study of silicon carrier dynamics,” Phys. Rev. B, 66, 165217 (2002).
C. W. Luo, Y. T. Wang, F. W. Chen, H. C. Shih, T. Kobayashi, “Eliminate coherence spike in reflection-type pump-probe measurements,” Optics Express, 17, 11321 (2009).
P. Uhd Jepsen, W. Schairer, I. H. Libon, U. Lemmer, N. E. Hecker, M. Birkholz, K. Lips, M. Schall, “Ultrafast carrier trapping in microcrystalline silicon observed in optical pump–terahertz probe measurements,” Appl. Phys. Lett., 79, 1291 (2001).
Y. Sakai, I. Kawayama, H. Nakanishi, M. Tonouchi, “Visualization of GaN surface potential using terahertz emission enhanced by local defects,” Scientific Reports, 5, 13860 (2015).
J. Nelson, The Physics of Solar cells (Imperial College Press, London, 2004) pp. 183.
Y. Arafat, F. M. Mohammedy, M. M. S. Hassan, “Optical and other measurement techniques of carrier lifetime in semiconductors,” International Journal of Optoelectronic Engineering, 2, 5(2012).
K. A. Salek, I. Kawayama, H. Murakami, M. Tonouchi, “Evaluation of surface carrier recombination of optically excited silicon using terahertz time-domain spectroscopy,” Terahertz Science and Technology, 7, 100(2014).
K. A. Salek, I. Kawayama, H. Murakami, M. Tonouchi, “Evaluation of solar cell using terahertz time-domain spectroscopy,” PSIJ, 6, 96(2015).
A. Luque, S. Hegedus, Handbook of Photovoltaic Science and Engineering (Wiley, Chichester, U.K., 2011) pp.112.
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We extend our appreciation to all staff members of SCREEN Holdings Co., Ltd. and Tonouchi Laboratory of Osaka University for their assistance and support.
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Nakanishi, H., Ito, A., Takayama, K. et al. Visualization of Photoexcited Carrier Responses in a Solar Cell Using Optical Pump—Terahertz Emission Probe Technique. J Infrared Milli Terahz Waves 37, 498–506 (2016). https://doi.org/10.1007/s10762-015-0233-x
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DOI: https://doi.org/10.1007/s10762-015-0233-x