Atomic Layer Deposition TiO2 Films and TiO2/SiNx Stacks Applied for Silicon Solar Cells
Source abstract
Abstract
Titanium oxide (TiO2) films and TiO2/SiNx stacks have potential in surface passivation, anti-reflection coatings and carrier-selective contact layers for crystalline Si solar cells. A Si wafer, deposited with 8-nm-thick TiO2 film by atomic layer deposition, has a surface recombination velocity as low as 14.93 cm/s at the injection level of 1.0 × 1015 cm−3. However, the performance of silicon surface passivation of the deposited TiO2 film declines as its thickness increases, probably because of the stress effects, phase transformation, atomic hydrogen and thermal stability of amorphous TiO2 films. For the characterization of 66-nm-thick TiO2 film, the results of transmission electron microscopy show that the anatase TiO2 crystallinity forms close to the surface of the Si. Secondary ion mass spectrometry shows the atomic hydrogen at the interface of TiO2 and Si which serves for chemical passivation. The crystal size of anatase TiO2 and the homogeneity of TiO2 film can be deduced by the measurements of Raman spectroscopy and spectroscopic ellipsometry, respectively. For the passivating contacts of solar cells, in addition, a stack composed of 8-nm-thick TiO2 film and a plasma-enhanced chemical-vapor-deposited 72-nm-thick SiNx layer has been investigated. From the results of the measurement of the reflectivity and effective carrier lifetime, TiO2/SiNx stacks on Si wafers perform with low reflectivity and some degree of surface passivation for the Si wafer.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Silicon and Solar Cell Technologies · Thin-Film Transistor Technologies · Semiconductor materials and devices
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan
Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan
Department of Materials Science and Engineering, National Dong Hwa University, Hualien 97401, Taiwan
Funding
Ministry of Science and Technology R.O.C.
References (40)
Show source-provided references
1. The path to 25% silicon solar sell efficiency: History of silicon cell evolution10.1002/pip.892 ↗
2. Surface passivation of crystalline silicon solar cells: A review10.1002/1099-159X(200009/10)8:5<473::AID-PIP337>3.0.CO;2-D ↗
3. Very low surface recombination velocities on p- and n-type c-Si by ultrafast spatial atomic layer deposition of aluminum oxide10.1063/1.3505311 ↗
4. Ge, J., Tang, M., Wong, J., Zhang, Z., Dippell, T., Doerr, M., Hohn, O., Huber, M., Wohlfart, P., and Aberle, A.G. (2014). Excellent silicon surface passivation achieved by industrial inductively coupled plasma deposited hydrogenated intrinsic amorphous silicon suboxide. In. J. Photoenergy, 2014.10.1155/2014/752967 ↗
5. Breitenstein, L., Richter, A., Hermle, M., and Warta, W. (2011, January 19–24). Impact of wet-chemical cleaning on the passivation quality of Al2O3 layers. Proceedings of the 37th IEEE Photovoltaic Specialists Conference, Seattle, WA, USA.10.1109/PVSC.2011.6186218 ↗
6. Schmidt, J., Veith, B., Werner, F., Zielke, D., and Brendel, R. (2010, January 20–25). Silicon surface passivation by ultrathin Al2O3 films and Al2O3/SiNx stacks. Proceedings of the 35th IEEE Photovoltaic Specialists Conference, Honolulu, HI, USA.
7. Hoex, B., Schmidt, J., Pohl, P., Van de Sanden, M.C.M., and Kessels, W.M.M. (2008). Silicon surface passivation by atomic layer deposited Al2O3. J. Appl. Phys., 104.10.1063/1.2963707 ↗
8. Spatially-separated atomic layer deposition of Al2O3, a new option for high-throughput Si solar cell passivation10.1002/pip.1092 ↗
9. Excellent passivation and low reflectivity with atomic layer deposited bilayer coatings for n-type silicon solar cells10.1016/j.tsf.2013.10.166 ↗
10. Tailoring the optical properties of APCVD titanium oxide films for all-oxide multi-layer anti-reflection coatings10.1109/JPHOTOV.2015.2437272 ↗
11. Stacked and nanolaminated Al2O3/TiO2 for surface passivation and encapsulation of silicon10.1002/pssr.201510143 ↗
12. Benner, F., Jordan, P.M., Richter, C., Simon, D.K., Dirnstorfer, I., Knaut, M., Bartha, J.W., and Mikolajick, T. (2014). Atomic layer deposited high-κ nanolaminates for silicon surface passivation. J. Vac. Sci. Technol. B, 32.10.1116/1.4863499 ↗
13. Al2O3-TiO2 nanolaminates for conductive silicon surface passivation10.1109/JPHOTOV.2015.2494695 ↗
14. Melskens, J., Van de Loo, B.W.H., Macco, B., Vos, M.F.J., Palmans, J., Smit, S., and Kessels, W.M.M. (2015, January 14–19). Concepts and prospects of passivating contacts for crystalline silicon solar cells. Proceedings of the 42nd IEEE Photovoltaic Specialists Conference, New Orleans, LA, USA.10.1109/PVSC.2015.7355646 ↗
15. Comparison of TiO2 and other dielectric coatings for buried contact solar cells: A review10.1002/pip.529 ↗
16. Lee, Y.-T., Lin, F.-R., Lin, T.C., Chen, C.-H., and Pei, Z. (2016). Low-temperature, chemically grown titanium oxide thin films with a high hole tunneling rate for Si solar cells. Energies, 9.10.3390/en9060402 ↗
17. Compressive study of rapid low-cost silicon surface passivation technologies10.1109/16.841230 ↗
18. Doeswijk, L.M., De Moor, H.H.C., Blank, D.H.A., and Rogalla, H. (1999). Passivating TiO2 coatings for silicon solar cells by pulsed laser deposition. Appl. Phys. A, 69.10.1007/s003390051427 ↗
19. Thomson, A.F., Lynn, S.Z., and McIntosh, K.R. (2010, January 6–10). Passivation of silicon by negatively charged TiO2. Proceedings of the 25th EUPVSEC, Valencia, Spain.
20. Light-enhanced surface passivation of TiO2-coated silicon10.1002/pip.1132 ↗
21. Yu, I.-S., Wang, Y.-W., Cheng, H.-E., Yang, Z.-P., and Lin, C.-T. (2013). Surface passivation and antireflection behavior of ALD TiO2 on n-type silicon for solar cells. Int. J. Photoenergy, 2013.10.1155/2013/431614 ↗
22. Liao, B., Hoex, B., Aberle, A.G., Chi, D., and Bhatia, C.S. (2014). Excellent c-Si surface passivation by low-temperature atomic layer deposited titanium oxide. Appl. Phys. Lett., 104.10.1063/1.4885096 ↗
23. Passivation of boron-doped industrial silicon emitters by thermal atomic layer deposited titanium oxide10.1109/JPHOTOV.2015.2434596 ↗
24. Avasthi, S., McClain, W.E., Mam, G., Kahn, A., Schwartz, J., and Sturm, J.C. (2013). Hole-blocking titanium-oxide/silicon heterojunction and its application to photovoltaics. Appl. Phys. Lett., 102.10.1063/1.4803446 ↗
25. Silicon heterojunction solar cells with electron selective TiOx contact10.1016/j.solmat.2016.01.020 ↗
26. High performance TiO2-based electron-selective contacts for crystalline silicon solar cells10.1002/adma.201600926 ↗
27. Ultrathin titanium dioxide nanolayers by atomic layer deposition for surface passivation of crystalline silicon10.1109/JPHOTOV.2016.2545404 ↗
28. Morphological and photoelectrochemical properties of ALD TiO2 films10.1149/1.2952659 ↗
29. Calibration of the WCT-100 photoconductance instrument at low conductance10.1002/pip.810 ↗
30. Sinton, R.A., Cuevas, A., and Stuckings, M. (1996, January 13–17). Quasi-steady-state photoconductance: A new method for solar cell material and device characterization. Proceedings of the 25th IEEE Photovoltaic Specialists Conference, Washington, DC, USA.10.1109/PVSC.1996.564042 ↗
31. Effect of thermally induced anatase-to-rutile phase transition in MOCVD growth TiO2 films on structural and optical properties10.1007/s003390100804 ↗
32. Yu, I.-S., Chang, I.-H., Cheng, H.-E., and Lin, Y.-S. (2014, January 8–13). Surface passivation of c-Si by atomic layer deposition TiO2 thin films deposited at low temperature. Proceedings of the 40th IEEE Photovoltaic Specialists Conference, Denver, CO, USA.10.1109/PVSC.2014.6925148 ↗
33. Experimental assessment of phonon confinement in TiO2 anatase nanocrystallites by Raman spectroscopy10.1002/jrs.3103 ↗
34. Raman line shapes of optical phonons of different symmetries in anatase TiO2 nanocrystals10.1021/jp9046193 ↗
35. Spectroscopic ellipsometry of thin film and bulk anatase (TiO2)10.1063/1.1573737 ↗
36. Single-material TiO2 double-layer antireflection coatings10.1016/S0927-0248(02)00473-7 ↗
37. PV Lighthouse. Available online: http://www.pvlighthouse.com.au/calculators/OPAL%202/OPAL%202.aspx.
38. Kane, D.E., and Swanson, R.M. (1985, January 21–25). Measurement of the emitter saturation current by a contactless photoconduc tivity decay method. Proceedings of the 18th IEEE Photovoltaic Specialists Conference, Las Vegas, NV, USA.
39. Rahman, M.Z., and Khan, S.I. (2012). Advances in surface passivation of c-Si solar cells. Mater. Renew. Sustain. Energy, 1.10.1007/s40243-012-0001-y ↗
40. Wan, Y., McIntosh, K.R., and Thomson, A.F. (2013). Characterisation and optimization of PECVD SiNx as an antireflection coating and passivation layer for silicon cells. AIP Adv., 3.10.1063/1.4795108 ↗