Broadband transparent conductive oxide layers with high
electron
mobility (μe) are essential to further
enhance crystalline silicon (c-Si) solar cell performances. Although
metallic cation-doped In2O3 thin films with
high μe (>60 cm2 V–1 s–1) have been extensively investigated,
the research regarding anion doping is still under development. In
particular, fluorine-doped indium oxide (IFO) shows promising optoelectrical
properties; however, they have not been tested on c-Si solar cells
with passivating contacts. Here, we investigate the properties of
hydrogenated IFO (IFO:H) films processed at low substrate temperature
and power density by varying the water vapor pressure during deposition.
The optimized IFO:H shows a remarkably high μe of 87 cm2 V–1 s–1, a carrier density of 1.2 × 1020 cm–3, and resistivity of 6.2 × 10–4 Ω cm.
Then, we analyzed the compositional, structural, and optoelectrical
properties of the optimal IFO:H film. The high quality of the layer
was confirmed by the low Urbach energy of 197 meV, compared to 444
meV obtained on the reference indium tin oxide. We implemented IFO:H
into different front/back-contacted solar cells with passivating contacts
processed at high and low temperatures, obtaining a significant short-circuit
current gain of 1.53 mA cm–2. The best solar cell
shows a conversion efficiency of 21.1%.