A highly transparent passivating contact (TPC) as front contact for crystalline silicon (c-Si) solar cells could in principle combine high conductivity, excellent surface passivation and high optical transparency. However, the simultaneous optimization of these features remains challenging. Here, we present a TPC consisting of a silicon-oxide tunnel layer followed by two layers of hydrogenated nanocrystalline silicon carbide (nc-SiC:H(n)) deposited at different temperatures and a sputtered indium tin oxide (ITO) layer (c-Si(n)/SiO2/nc-SiC:H(n)/ITO). While the wide band gap of nc-SiC:H(n) ensures high optical transparency, the double layer design enables good passivation and high conductivity translating into an improved short-circuit current density (40.87 mA cm−2), fill factor (80.9%) and efficiency of 23.99 ± 0.29% (certified). Additionally, this contact avoids the need for additional hydrogenation or high-temperature postdeposition annealing steps. We investigate the passivation mechanism and working principle of the TPC and provide a loss analysis based on numerical simulations outlining pathways towards conversion efficiencies of 26%.

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Silicon oxide nanowires SiOx were synthesized by the gas‐jet electron beam plasma chemical vapor deposition method. The synthesis of nanostructures was carried out on silicon substrates with thin tin film as a catalyst. The evolution in the morphology of the obtained structures was investigated while changing the substrate temperature in the range 200–415 °C. Dense array of aligned nanowire bundles (microropes) is formed at a temperatures of 335 and 415 °C. With decrease in the temperature to 270 and 245 °C arrays of microropes transform into cocoon‐like structures of nanowires. At a temperature 200 °С, array formed almost entirely consisting of cocoon‐like structures. The results of X‐ray energy dispersive spectroscopy (EDS) of the nanowires show that the ratio of oxygen to silicon is on average Si:O = 1:2.4. At the same time, Fourier Transform Infrared spectroscopy (FTIR) analysis of the obtained nanostructures showed that the synthesized nanowires consist of SiOx with x around 2. Moreover, the composition of the structures remains practically unchanged with the variation of the substrate temperature. The IR spectra show bands due to both Si–OH bonds and water molecules. Measurements of contact angles for water showed that the nanowire film surface synthesized in this work is hydrophilic in nature. When structuring involves the oriented growth microropes, the contact angle is about 20–35°. Decreasing of the substrate temperature and formation of cocoon‐like structures leads to a decrease in the contact angle to 4–12°. The photoluminescence (PL) spectra of nanostructures synthesized at the different substrate temperatures consist of a broad band with a maximum around 2.5 eV when using laser at 325 nm as the exciting source. We assume that the composition of the nanowires is close to SiO2, and the excess of oxygen in structures composition is due to the influence of adsorbed water molecules and hydroxyl groups with the formation of Si–OH bonds. Apparently, these bonds define the photoluminescence spectrum.

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