Progressive smart photovoltaic technologies including heterostructures a-SiC/c-Si with ITO antireflection film are one of the prospective replacements of conventional photovoltaic silicon technology. The main advantages include acceptable efficiency, material savings, environmentally friendly production, acceptable service life and cost [1, 2, 3].
Our paper is focused on the investigation of heterostructures (a-SiC/c-Si) provided with a layer of ITO (indium oxide/tin oxide 90/10 wt.%) which acts as a passivating and antireflection coating. Photolitography and lift off technique was used for Al grid preparation as top contact of solar cell structure. Bottom whole area Al ohmic contact was prepared by Al evaporation. Prepared photovoltaic cell structure underwent the investigation of the temperature on its operation. The investigation of the dynamic properties of heterojunction PV cell was carried out using impedance spectroscopy where the Agilent LCR Meter 4284A was used. An example of the results – selected impedance spectra – Nyquist characteristics obtained on sample coated with ITO is shown in Fig. 1.
The equivalent AC circuit best approximated the measured impedance data using numerical process was proposed. Assessment of the effect of the temperature on the operation of prepared heterostructure was carried out by analysis of the temperature dependence of AC circuit elements. For a more comprehensive characterization the activation energies and relaxation times were also determined. Impedance spectra were also measured at different DC bias voltages due to a more detailed understanding of transport phenomenon in the heterostructure.
Acknowledgement
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-15-0326.
References
[1] I.A. Yunaz, K. Hashizume, S. Miyajima, A. Yamada, M. Konagai, Solar Energy Materials & Solar Cells 93, 1056–1061 (2009).
[2] S. Janz, S. Reber, W. Glunz, Proceedings of the 21st EUPVSEC, 660-663 (2006).
[3] V.A. Dao, H. Choi, J.Heo, H.Park, K.Yoon, Y. Lee,Y. Kim, N. Lakshminarayan, J. Yi, Current Applied Physics 10, S506–S509 (2010).
Photovoltaics and solar cells at nanoscale , Nanotechnology for environment and energy
