Proceedings of International Conference Asia-Pacific Hybrid and Organic Photovoltaics (AP-HOPV17)
Publication date: 7th November 2016
Semiconducting epi-Si1-xGex alloys has promising features as a solar cell material and field-effect transistors [1-2]. The band gap of epi-Si1-xGex can be tuned in between 0.66 and 1.12 eV as a function of Ge composition (x)[3]. About 40% efficiency is expected from 1.8 eV/1.4 eV/0.9–1.0 eV, tandem solar cell, under concentrated sunlight [3-4,5]. However, using Si1-xGex has serveral challenges: first to overcome the reduction in short circuit current density, Jsc due to the lattice mismatch, the threading dislocations (TDD) can propagat to the active layer. We also need to improve the open circuit voltage, Voc due to the increased dark current from smaller bandgap. And second is the current matching issue for tandem structure SiGe bottom cell (0.9–1.0 eV). Until now very limited work has been done about the low composition of Ge, 10 % in strained epi-Si1-xGex /c-Si and insertion of Si buffer layer to grow low TDD heterojunction (HET) solar cell and to get spectral shift toward the long wavelength side for better current matching [5-6]. Therefore, in this work we choose 10% Ge to make fully strained n-Si0.93 Ge0.07 epilayer on the over layer of Si buffer layer grown by MBE and then it was used to make a-Si:H (HET) solar cell using CVD. Thanks to the c-Si buffer layer at the hetero-interface, where the performance of the cells was improved from 2.3 % efficiency with Jsc, 7.90 mA/cm2, Voc, 433 mV and Fil Factor (FF), 0.666, to the efficiency, 3.5 % for the epi-SiGe with Jsc, 15.46 mA/cm2, Voc, 418 mV and with FF, 0.539. This result indicates that one on hand we found slight decrease in Voc and FF but on other side the Jsc were drastically enhanced to 15.46 mA/cm2.
References
[1] Said, et al., Thin Solid Films 337, 85 (1999).
[2] Shiraki, et al., Surf. Sci. Rep. 59, 153 (2005).
[3] Friedman, et al., J. Cryst. Growth 195, 409 (1998).
[4] R. Varache, et al., Solar Energy Materials and Solar Cells 141 (2015) 14–23
[5] Hadi, et al., Mater. Res. Soc. Symp. Proc. Vol. 1447 © 2012 Materials Research Society.
[6] Oshima, et al., Japanese Journal of Applied Physics 54, 012301 (2015).
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.