A Čampa; F Smole; N Folchert; T Wietler; B Min; R Brendel; M Topič
In: IEEE Journal of Photovoltaics, Bd. 9, Nr. 6, S. 1575-1582, 2019.
@article{Čampa2019,
title = {Detailed Analysis and Understanding of the Transport Mechanism of Poly-Si-Based Carrier Selective Junctions},
author = {A Čampa and F Smole and N Folchert and T Wietler and B Min and R Brendel and M Topič},
doi = {10.1109/JPHOTOV.2019.2943610},
year = {2019},
date = {2019-11-01},
journal = {IEEE Journal of Photovoltaics},
volume = {9},
number = {6},
pages = {1575-1582},
abstract = {We investigate the transport mechanism of poly-Si-based carrier-selective junctions using the two-dimensional numerical semiconductor device simulations. The detailed transport model considers the charge carrier transport through the pinholes as well as tunneling through a very thin silicon oxide simultaneously. For the verification of the simulation model, the complete temperature dependent transfer length method is modeled and its results are verified with measurements of two different samples. By means of rigorous simulations, the influence of different pinhole geometrical and material parameters on junction resistivity are investigated and explained in detail. From the presented results, the fundamental understanding needed for optimizing the poly-Si-based carrier selective junction in respect to the main design parameters such as doping level in poly-Si, annealing time, silicon oxide thickness, and pinhole density is given. The detailed analysis shows the pinhole channel plays the most crucial role in the design of poly-Si-based carrier-selective junctions if the silicon oxide layer thickness is larger than 2 nm.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
D Tetzlaff; J Krügener; Y Larionova; S Reiter; M Turcu; F Haase; R Brendel; R Peibst; U Höhne; J -D Kähler; T F Wietler
In: Solar Energy Materials and Solar Cells, Bd. 173, S. 106-110, 2017, ISSN: 0927-0248, (Proceedings of the 7th international conference on Crystalline Silicon Photovoltaics).
@article{Tetzlaff2017c,
title = {A simple method for pinhole detection in carrier selective POLO-junctions for high efficiency silicon solar cells},
author = {D Tetzlaff and J Krügener and Y Larionova and S Reiter and M Turcu and F Haase and R Brendel and R Peibst and U Höhne and J -D Kähler and T F Wietler},
doi = {10.1016/j.solmat.2017.05.041},
issn = {0927-0248},
year = {2017},
date = {2017-12-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {173},
pages = {106-110},
abstract = {Polycrystalline silicon (poly-Si) layers on thin silicon oxide films have received strong research interest as they form excellent carrier selective junctions on crystalline silicon substrates after appropriate thermal processing. Recently, we presented a new method to determine the pinhole density in interfacial oxide films of poly-Si on oxide (POLO)-junctions with excellent electrical properties. The concept of magnification of nanometer-size pinholes in the interfacial oxide by selective etching of the underlying crystalline silicon is used to investigate the influence of annealing temperature on pinhole densities. Eventually, the pinholes are detected by optical microscopy and scanning electron microscopy. We present results on the pinhole density in POLO-junctions with J0 values as low as 1.4 fA/cm2. The stability of this method is demonstrated by proving that no new holes are introduced to the oxide during the etching procedure for a wide range of etching times. Finally, we show the applicability to multiple oxide types and thickness values, differently doped poly-Si layers as well as several types of wafer surface morphologies. For wet chemically grown oxides, we verified the existence of pinholes with an areal density of 2×10^7 cm−2 even already after annealing at a temperature of 750 °C (lower than the optimum annealing temperature for these junctions).},
note = {Proceedings of the 7th international conference on Crystalline Silicon Photovoltaics},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
D Tetzlaff; M Dzinnik; J Krügener; Y Larionova; S Reiter; M Turcu; R Peibst; U Höhne; J-D Kähler; T F Wietler
In: Energy Procedia, Bd. 124, Nr. Supplement C, S. 435-440, 2017, ISSN: 1876-6102, (7th International Conference on Silicon Photovoltaics, SiliconPV 2017, 3-5 April 2017, Freiburg, Germany).
@article{Tetzlaff2017cb,
title = {Introducing pinhole magnification by selective etching: application to poly-Si on ultra-thin silicon oxide films},
author = {D Tetzlaff and M Dzinnik and J Krügener and Y Larionova and S Reiter and M Turcu and R Peibst and U Höhne and J-D Kähler and T F Wietler},
doi = {10.1016/j.egypro.2017.09.270},
issn = {1876-6102},
year = {2017},
date = {2017-09-21},
journal = {Energy Procedia},
volume = {124},
number = {Supplement C},
pages = {435-440},
abstract = {Carrier selective junctions formed by polycrystalline silicon (poly-Si) on ultra-thin silicon oxide films are currently in the spotlight of silicon photovoltaics. We develop a simple method using selective etching and conventional optical microscopy to determine the pinhole density in interfacial oxide films of poly-Si on oxide (POLO)-junctions with excellent electrical properties. We characterize the selective etching of poly-Si versus ultra-thin silicon oxide. We use test structures with deliberately patterned openings and 3 nm thin oxide films to check the feasibility of magnification by undercutting the interfacial oxide. With the successful proof of our concept we introduce a new method to access the density of nanometer-size pinholes in POLO-junctions with excellent passivation properties.},
note = {7th International Conference on Silicon Photovoltaics, SiliconPV 2017, 3-5 April 2017, Freiburg, Germany},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
D Tetzlaff; J Krügener; Y Larionova; S Reiter; M Turcu; R Peibst; U Höhne; J -D Kähler; T Wietler
Evolution of oxide disruptions: The (w)hole story about passivating contacts Proceedings Article
In: IEEE, (Hrsg.): 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), S. 0221-0224, Portland, OR, USA, 2016, ISBN: 978-1-5090-2725-5.
@inproceedings{Tetzlaff2016,
title = {Evolution of oxide disruptions: The (w)hole story about passivating contacts},
author = {D Tetzlaff and J Krügener and Y Larionova and S Reiter and M Turcu and R Peibst and U Höhne and J -D Kähler and T Wietler},
editor = {IEEE},
doi = {10.1109/PVSC.2016.7749582},
isbn = {978-1-5090-2725-5},
year = {2016},
date = {2016-06-01},
booktitle = {2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)},
journal = {Proceedings of the 43rd IEEE Photovoltaic Specialists Conference},
pages = {0221-0224},
address = {Portland, OR, USA},
abstract = {Different models exist describing the current transport in polycrystalline Si/SiOx/crystalline Si junctions. Besides tunneling through thin oxides, transport through pinholes is discussed. We investigate the influence of annealing temperature on the structural properties of polycrystalline Si/SiOx/crystalline Si interfaces and analyze the formation and evolution of holes by high resolution transmission electron microscopy in comparison to electrical results. We prove the existence of pinholes in samples with good electrical properties in agreement with the pinhole model.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}