Journal of Solar Energy Research

Two-Junction Silicon Vertical Solar Cells: A Comparison of Tunnel Junction and Metallic Contact Connections

Document Type : Research Article

Authors

1 Physics department, Urgench State University, P.O. Box: 220100, Urgench, Uzbekistan.

2 Department of Electronics and Radiotechnics, Tashkent University of Information Technologies, P.O. Box: 200100, Tashkent, Uzbekistan.

3 Institute of Smart Systems Technologies, University of Klagenfurt, P.O. Box: 9020, Klagenfurt, Austria.

Abstract

In this work, the modelling of a two-junction vertical silicon solar cell is presented. The primary focus is on comparing the characteristics and performance parameters of the device when either a tunnel junction or a metallic layer is employed as the interconnect between the subcells. The advantages and limitations of fabrication technologies for vertical solar cells incorporating either a tunnel junction or a metallic interlayer as the inter-subcell contact are discussed. For the tunnel-junction-based structure, the simulation framework and set of parameters used in the modeling are described in detail. By fitting the simulated and experimental I-V characteristics of the tunnel junction, the following parameters were extracted: the effective masses at the band edges mc=0.212m0, mv=0.178m0, as well as the Huang–Rhys factor S=1.29. Comparative results for the dependence of conversion efficiency on solar concentration are also presented. It is shown that, for the considered geometrical dimensions, the efficiency differences between the analyzed device configurations are minimal. For both types of solar cells, the conversion efficiency increases approximately linearly with solar concentration up to approximately 200 suns, reaches a saturation region, and then begins to decrease at concentrations exceeding approximately 500 suns.

Keywords

[1] Atamuratov, A. E., Jabbarova, B. O., Khalilloev, M. M., Rajapov, D. R., Yusupov, A., Chedjou, J. C., Blugan, G., & Saidov, K. (2025). Impact of source (drain) doping profiles and channel doping level on self-heating effect in FinFET. Micro and Nanostructures, 197, 208015. https://doi.org/10.1016/j.micrna.2024.208015
[2] Atamuratov, A. E., Yusupov, A., Atamuratova, Z. A., Chedjou, J. C., & Kyamakya, K. (2020). Lateral Capacitance–Voltage Method of NanoMOSFET for Detecting the Hot Carrier Injection. Applied Sciences, 10(21), 7935. https://doi.org/10.3390/app10217935
[3] Atamuratov, A., Jumaboyev, B., Yusupov, A., Abdikarimov, A., & Loureiro, A. (2022). The effect of geometrical sizes on efficiency of vertical silicon tunnel junction solar cell for high solar concentration. 2022 International Conference on Information Science and Communications Technologies (ICISCT), https://doi.org/10.1109/ICISCT55600.2022.10146907
[4] Atamuratov, A., Jumaboyev, B., Abdikarimov, A., Yusupov, A., & Loureiro, A. (2023). The Effect of Height on the Efficiency of Vertical Silicon Tunnel Junction Solar Cell for High Solar Concentration. 2023 14th Spanish Conference on Electron Devices (CDE), https://doi.org/10.1109/CDE58627.2023.10339414
[5] Ferrer-Rodríguez, J. P., Fernández, E. F., Almonacid, F., & Pérez-Higueras, P. (2016). Optical design of a 4-off-axis-unit Cassegrain ultra-high concentrator photovoltaics module with a central receiver. Optics Letters, 41(9), 1985–1988. https://doi.org/10.1364/OL.41.001985
[6] Shanks, K., Ferrer-Rodriguez, J. P., Fernández, E. F., Almonacid, F., Pérez-Higueras, P., Senthilarasu, S., & Mallick, T. (2018). A> 3000 suns high concentrator photovoltaic design based on multiple Fresnel lens primaries focusing to one central solar cell. Solar Energy, 169, 457–467. https://doi.org/10.1016/j.solener.2018.05.016
[7] Guk, E., Nalet, T., Shvarts, M., & Shuman, V. (1997). Characteristic features of silicon multijunction solar cells with vertical pn junctions. Semiconductors, 31(7), 726–727. https://doi.org/10.1134/1.1187077
[8] Sater, B. L., & Sater, N. D. (2002). High voltage silicon VMJ solar cells for up to 1000 suns intensities. Conference Record of the Twenty-Ninth IEEE Photovoltaic Specialists Conference, 2002., https://doi.org/10.1109/PVSC.2002.1190778
[9] Geisz, J., Olson, J., Friedman, D., Jones, K., Reedy, R., & Romero, M. (2005). Lattice-matched GaNPAs-on-silicon tandem solar cells. Conference Record of the Thirty-first IEEE Photovoltaic Specialists Conference, 2005., https://doi.org/10.1109/PVSC.2005.1488226
[10] Derendorf, K., Essig, S., Oliva, E., Klinger, V., Roesener, T., Philipps, S. P., Benick, J., Hermle, M., Schachtner, M., & Siefer, G. (2013). Fabrication of GaInP/GaAs//Si solar cells by surface activated direct wafer bonding. IEEE Journal of Photovoltaics, 3(4), 1423–1428. https://doi.org/10.1109/JPHOTOV.2013.2273097
[11] Mailoa, J. P., Bailie, C. D., Johlin, E. C., Hoke, E. T., Akey, A. J., Nguyen, W. H., McGehee, M. D., & Buonassisi, T. (2015). A 2-terminal perovskite/silicon multijunction solar cell enabled by a silicon tunnel junction. Applied Physics Letters, 106(12). https://doi.org/10.1063/1.4914179
[12] Jain, N., & Hudait, M. K. (2014). III–V multijunction solar cell integration with silicon: Present status, challenges and future outlook. Energy Harvesting and Systems, 1(3-4), 121–145. https://doi.org/10.1515/ehs-2014-0012
[13] Esaki, L. (1958). New phenomenon in narrow germanium p− n junctions. Physical review, 109(2), 603. https://doi.org/10.1103/PhysRev.109.603
[14] Fave, A., Lelièvre, J.-F., Gallet, T., Su, Q., & Lemiti, M. (2017). Fabrication of Si tunnel diodes for c-Si based tandem solar cells using proximity rapid thermal diffusion. Energy Procedia, 124, 577–583. https://doi.org/10.1016/j.egypro.2017.09.281
[15] Wang, J., Wheeler, D., Yan, Y., Zhao, J., Howard, S., & Seabaugh, A. (2002). Silicon tunnel diodes formed by proximity rapid thermal diffusion. Proceedings. IEEE Lester Eastman Conference on High Performance Devices, https://doi.org/10.1109/LED.2002.807706
[16] Bae, J., Yousuf, H., Khokhar, M. Q., Madara, P. C., Jang, S., Chu, M., Aida, M. N., Jony, J. A., Kim, E., & Park, S. (2025). High-efficiency mechanically stacked bifacial III-V/HJT multijunction solar cell enabled by spectral albedo. Sustainable Energy Technologies and Assessments, 83, 104616. https://doi.org/10.1016/j.seta.2025.104616
[17] Zhang, J., Wang, R., Zhao, W., Zhang, H., Xu, Y., Wang, J., Zhong, X., Shen, F., Yao, L., & Ren, H. (2025). Guided growth of vertically aligned 2D perovskites improves the performance of monolithic perovskite/organic tandem solar cells. Chemical Engineering Journal, 170523. https://doi.org/10.1016/j.cej.2025.170523
[18] Im Noh, Y., Kim, C. U., & Choi, K. J. (2025). Perovskite/Homojunction-silicon tandem solar cells with optimized silicon nitride passivation and advanced double-sided ohmic contacts. Materials Today Energy, 52, 101917. https://doi.org/10.1016/j.mtener.2025.101917
[19] Pozner, R., Segev, G., Sarfaty, R., Kribus, A., & Rosenwaks, Y. (2012). Vertical junction Si cells for concentrating photovoltaics. Progress in Photovoltaics: Research and applications, 20(2), 197–208. https://doi.org/10.1002/pip.1118
[20] Xing, Y., Han, P., Wang, S., Fan, Y., Liang, P., Ye, Z., Li, X., Hu, S., Lou, S., & Zhao, C. (2013). Performance analysis of vertical multi-junction solar cell with front surface diffusion for high concentration. Solar Energy, 94, 8–18. https://doi.org/10.1016/j.solener.2013.04.030
[21] Yan, Y. (2008). Silicon-based tunnel diode technology. University of Notre Dame.
[22] Hermle, M., Létay, G., Philipps, S. P., & Bett, A. W. (2008). Numerical simulation of tunnel diodes for multi‐junction solar cells. Progress in Photovoltaics: Research and applications, 16(5), 409–418. https://doi.org/10.1002/pip.824
[23] Sze, S. M., & Ng, K. K. (2006). Physics of Semiconductor Devices. Wiley.
[24] Ieong, M., Solomon, P. M., Laux, S., Wong, H.-S., & Chidambarrao, D. (1998). Comparison of raised and Schottky source/drain MOSFETs using a novel tunneling contact model. International Electron Devices Meeting 1998. Technical Digest (Cat. No. 98CH36217), https://doi.org/10.1109/IEDM.1998.746461
[25] Gaspar, G., Serra, J. M., Kern, J., & Müller, M. (2023). TCAD simulation of electrical characteristics of silicon tunnel junctions for monolithically integrated silicon/perovskite tandem solar cells. AIP Conference Proceedings, https://doi.org/10.1063/5.0141125
[26] Synopsys, I. (2018). Sentaurus™ Device User Guide.
[27] Shockley, W., & Read Jr, W. (1952). Statistics of the recombinations of holes and electrons. Physical review, 87(5), 835. https://doi.org/10.1103/PhysRev.87.835
[28] Schenk, A. (1992). A model for the field and temperature dependence of Shockley-Read-Hall lifetimes in silicon. Solid-State Electronics, 35(11), 1585–1596. https://doi.org/10.1016/0038-1101(92)90184-E
[29] Sentaurus, T. (2018). Version O-2018.06. Synopsys, Mountain View, CA, USA.
[30] Takagahara, T. (1996). Electron—phonon interactions in semiconductor nanocrystals. Journal of Luminescence, 70(1-6), 129–143. https://doi.org/10.1016/0022-2313(96)00050-6
[31] Elnaggar, M., Elogail, Y., Fedawy, M., & Shaker, A. (2026). A Comprehensive Review on III-V TFET Design Optimization. Micro and Nanostructures, 208601. https://doi.org/10.1016/j.micrna.2026.208601
[32] Kim, K. (2026). Stacked Si/GaN tunnel junction flip-chip light-emitting diodes with improved external quantum efficiency. Results in Physics, 108623. https://doi.org/10.1016/j.rinp.2026.108623
Journal of Solar Energy Research
Volume 11, Issue 2
April 2026
Pages 3027-3040