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Near-Infrared Light Management in Silicon Heterojunction Solar Cells for Silicon-Based III–V Multijunction Tandem Cell Applications
H. Lee, T. Nishihara, Y. Ohshita, A. Ogura
Heterojunction, Optical Losses, Tandem, TCO Transparent Conducting Oxides, Silicon Solar Cell
Evolving and Emerging Technologies: Tandems; Thin Film absorbers; III-V; New Materials and Concepts; Advanced Modelling
Subtopic: Tandems
Event: 8th World Conference on Photovoltaic Energy Conversion
Session: 2AV.3.15
362 - 365
ISBN: 3-936338-86-8
Paper DOI: 10.4229/WCPEC-82022-2AV.3.15
0,00 EUR
Document(s): paper


The silicon heterojunction (SHJ) cell technology dominates in Si-based tandem cell research, and also the world record Si-based III–V multijunction tandem cell is based on SHJ bottom cells. Despite this exciting performance, the tandem cell was still limited by the SHJ bottom-cell photocurrent. The limited photocurrent is owing to significant losses in the near-infrared (NIR) part of the spectrum on the rear side of SHJ bottom cells. This contribution demonstrates an improved NIR response of the tungsten-doped indium oxide (IWO)/Ag rear contact of rear-junction SHJ solar cells. The carrier concentration and the thickness of the rear IWO layer are optimized in order to minimize the free-carrier and the plasmonic absorption losses without detrimentally affecting the selectivity and the electrical transport properties of SHJ solar cells. The NIR light reflectance of rear IWO/Ag reflectors are shown to be significantly impacted by the carrier concentration of IWO layers within the investigated ranges. As a result of these optimizations, a significant decrease of the parasitic absorption loss in the NIR part of the spectrum is achieved, leading to a champion device with a short-circuit current density of up to 40.8 mA/cm2 and an efficiency of 22.4%.