LabAdviser/Technology Research/Technology for CZTS-Silicon Tandem Solar Cells: Difference between revisions
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In this thesis, we chose CuZnSnS4, a quaternary compound semiconductor with a bandgap of 1.5 eV, as a promising non-toxic, earth-abundant, and cheap representative candidate from the chalcogenide family, and systematically studied the integration challenges with silicon. For this purpose, we developed and optimized a thermally resilient silicon cell structure with polysilicon carrier selective contacts, and used an ultrathin (< 10 nm) titanium nitride-based diffusion barrier at the interface of the two cells (called the “barrier layer”) to protect the silicon cell against contamination. Throughout the thesis, we showed that the performance of the CZTS-Si tandem devices heavily relies on the electrical, optical, and protection behavior of the barrier layer. By proper engineering of the TiN and polysilicon interfacial layers, we managed to keep the silicon cell almost intact during the full fabrication of CZTS, and demonstrated a world-record efficiency of 4.1% for this type structure. Our findings implicate that the growth of new materials, with a wide range of thermal budgets and compositions, is technically feasible on silicon. Moreover, we believe that our proposed tandem structure may provide new insights for the Si community in terms of device architecture engineering for future silicon-based tandem cells. | In this thesis, we chose CuZnSnS4, a quaternary compound semiconductor with a bandgap of 1.5 eV, as a promising non-toxic, earth-abundant, and cheap representative candidate from the chalcogenide family, and systematically studied the integration challenges with silicon. For this purpose, we developed and optimized a thermally resilient silicon cell structure with polysilicon carrier selective contacts, and used an ultrathin (< 10 nm) titanium nitride-based diffusion barrier at the interface of the two cells (called the “barrier layer”) to protect the silicon cell against contamination. Throughout the thesis, we showed that the performance of the CZTS-Si tandem devices heavily relies on the electrical, optical, and protection behavior of the barrier layer. By proper engineering of the TiN and polysilicon interfacial layers, we managed to keep the silicon cell almost intact during the full fabrication of CZTS, and demonstrated a world-record efficiency of 4.1% for this type structure. Our findings implicate that the growth of new materials, with a wide range of thermal budgets and compositions, is technically feasible on silicon. Moreover, we believe that our proposed tandem structure may provide new insights for the Si community in terms of device architecture engineering for future silicon-based tandem cells. | ||
==Publications | ==Publications in peer-reviewed journal papers== | ||
The results achieved during the ph.d. project have been published on some peer-reviewed journals, which are listed as below: | |||
=== | ===Publications as first author === | ||
'''[1]''' Hajijafarassar, A., Martinho, F., Stulen, F., Grini, S., López-Mariño, S., Espíndola-Rodríguez, M., Döbeli, M., Canulescu, S., Stamate, E., Gansukh, M., Engberg, S., Crovetto, A., Vines, L., Schou, J., & Hansen, O. (2020). Monolithic thin-film chalcogenide–silicon tandem solar cells enabled by a diffusion barrier. Solar Energy Materials and Solar Cells, 207, 110334. https://doi.org/10.1016/j.solmat.2019.110334 | |||
'''[2]''' Martinho, F., Hajijafarassar, A., Lopez-Marino, S., Espíndola-Rodríguez, M., Engberg, S., Gansukh, M., Stulen, F., Grini, S., Canulescu, S., Stamate, E., Crovetto, A., Vines, L., Schou, J., & Hansen, O. (2020). Nitride-Based Interfacial Layers for Monolithic Tandem Integration of New Solar Energy Materials on Si: The Case of CZTS. ACS Applied Energy Materials, 3(5), 4600–4609. https://doi.org/10.1021/acsaem.0c00280 (Equal Contribution) | |||
===Publications as co-author === | |||
'''[1]''' Crovetto, A., Hajijafarassar, A., Hansen, O., Seger, B., Chorkendorff, I., & Vesborg, P. C. K. (2020). Parallel Evaluation of the BiI 3 , BiOI, and Ag 3 BiI 6 Layered Photoabsorbers. Chemistry of Materials, 32(8), 3385–3395. https://doi.org/10.1021/acs.chemmater.9b04925 | |||
'''[2]''' Crovetto, A., Børsting, K., Nielsen, R., Hajijafarassar, A., Hansen, O., Seger, B., Chorkendorff, I., & Vesborg, P. C. K. (2020). TaS 2 Back Contact Improving Oxide-Converted Cu2BaSnS4 Solar Cells. ACS Applied Energy Materials, 3(1), 1190–1198. https://doi.org/10.1021/acsaem.9b02251 | |||
'''[3]''' Martinho, F., Lopez-Marino, S., Espíndola-Rodríguez, M., Hajijafarassar, A., Stulen, F., Grini, S., Döbeli, M., Gansukh, M., Engberg, S., Stamate, E., Vines, L., Schou, J., Hansen, O., & Canulescu, S. (2020). Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review. ACS Applied Materials & Interfaces, 12(35), 39405–39424. https://doi.org/10.1021/acsami.0c10068 | |||
'''[4]''' Gansukh, M., López Mariño, S., Espindola Rodriguez, M., Engberg, S. L. J., Martinho, F. M. A., Hajijafarassar, A., Schjødt, N. C., Stamate, E., Hansen, O., Schou, J., & Canulescu, S. (2020). Oxide route for production of Cu2ZnSnS4 solar cells by pulsed laser deposition. Solar Energy Materials and Solar Cells, 215, 110605. https://doi.org/10.1016/j.solmat.2020.110605 | |||
==Fabrication: Process flows == | ==Fabrication: Process flows == | ||