TY - JOUR
T1 - Passivation at the interface between liquid-phase crystallized silicon and silicon oxynitride in thin film solar cells
AU - Preissler, Natalie
AU - Töfflinger, Jan Amaru
AU - Gabriel, Onno
AU - Sonntag, Paul
AU - Amkreutz, Daniel
AU - Stannowski, Bernd
AU - Rech, Bernd
AU - Schlatmann, Rutger
N1 - Publisher Copyright:
Copyright © 2016 John Wiley & Sons, Ltd.
PY - 2017/7
Y1 - 2017/7
N2 - The passivation quality at the interface between liquid-phase crystallized silicon (LPC-Si) and a dielectric interlayer (IL) was investigated in terms of the defect state density at the IL/LPC-Si interface (Dit) as well as the effective fixed charge density in the IL (QIL,eff). Both parameters were obtained via high-frequency capacitance–voltage measurements on developed metal–insulator–semiconductor structures based on a molybdenum layer sandwiched between the IL and the glass substrate. Dit and QIL,eff were correlated to the open circuit voltage (Voc) and the integrated external quantum efficiency (Jsc,EQE) obtained on corresponding solar cell structures as well as to Voc and Jsc,EQE results based on two-dimensional simulations. We found that Dit was reduced by one order of magnitude using a hydrogen plasma treatment (HPT) at 400 °C. Irrespectively of the HPT, QIL,eff was > 1012 cm−2. We suggest that field-effect passivation dominates chemical passivation at the IL/n-type LPC-Si interface. We attribute the significant enhancement of Voc and Jsc,EQE observed after HPT on n-type LPC-Si solar cells mainly to improvements of the passivation quality in the n-type LPC-Si bulk rather than at the IL/n-type LPC-Si interface. For p-type absorbers, the HPT did not improve Voc and Jsc,EQE significantly. We propose that this is because of an insufficient passivation of bulk defects by positively charged hydrogen, which dominates in p-type silicon, in combination with an insufficient interface passivation.
AB - The passivation quality at the interface between liquid-phase crystallized silicon (LPC-Si) and a dielectric interlayer (IL) was investigated in terms of the defect state density at the IL/LPC-Si interface (Dit) as well as the effective fixed charge density in the IL (QIL,eff). Both parameters were obtained via high-frequency capacitance–voltage measurements on developed metal–insulator–semiconductor structures based on a molybdenum layer sandwiched between the IL and the glass substrate. Dit and QIL,eff were correlated to the open circuit voltage (Voc) and the integrated external quantum efficiency (Jsc,EQE) obtained on corresponding solar cell structures as well as to Voc and Jsc,EQE results based on two-dimensional simulations. We found that Dit was reduced by one order of magnitude using a hydrogen plasma treatment (HPT) at 400 °C. Irrespectively of the HPT, QIL,eff was > 1012 cm−2. We suggest that field-effect passivation dominates chemical passivation at the IL/n-type LPC-Si interface. We attribute the significant enhancement of Voc and Jsc,EQE observed after HPT on n-type LPC-Si solar cells mainly to improvements of the passivation quality in the n-type LPC-Si bulk rather than at the IL/n-type LPC-Si interface. For p-type absorbers, the HPT did not improve Voc and Jsc,EQE significantly. We propose that this is because of an insufficient passivation of bulk defects by positively charged hydrogen, which dominates in p-type silicon, in combination with an insufficient interface passivation.
KW - capacitance–voltage
KW - liquid-phase crystallization
KW - measurements
KW - passivation
KW - thin film solar cells
UR - https://www.scopus.com/pages/publications/85028245328
U2 - 10.1002/pip.2852
DO - 10.1002/pip.2852
M3 - Article
AN - SCOPUS:85028245328
SN - 1062-7995
VL - 25
SP - 515
EP - 524
JO - Progress in Photovoltaics: Research and Applications
JF - Progress in Photovoltaics: Research and Applications
IS - 7
ER -
