No abstract

Hydrogen-doped indium oxide (IO:H) has recently garnered attention as a high-performance transparent conducting oxide (TCO) and has been incorporated into a wide array of photovoltaic devices due to its high electron mobility (>100 cm2/V s) and transparency (>90% in the visible range). Here, we demonstrate IO:H thin-films deposited by sputtering with mobilities in the wide range of 10–100 cm2/V s and carrier densities of 4 × 1018 cm–3–4.5 × 1020 cm–3 with a large range of hydrogen incorporation. We use the temperature-dependent Hall mobility from 5 to 300 K to determine the limiting electron scattering mechanisms for each film and identify the temperature ranges over which these remain significant. We find that at high hydrogen concentrations, the grain size is reduced, causing the onset of grain boundary scattering. At lower hydrogen concentrations, a combination of ionized impurity and polar optical phonon scattering limits mobility. We find that the influence of ionized impurity scattering is reduced with the increasing hydrogen content, allowing a maximization of mobility >100 cm2/V s at moderate hydrogen incorporation amounts prior to the onset of grain boundary scattering. By investigating the parameter space of the hydrogen content, temperature, and grain size, we define the three distinct regions in which the grain boundary, ionized impurity, and polar optical phonon scattering operate in this high mobility TCO.

Improving the conductivity of earth-abundant transparent conductive oxides (TCOs) remains an important challenge that will facilitate the replacement of indium-based TCOs. Here, we show that a hydrogen (H2)-plasma post-deposition treatment improves the conductivity of amorphous aluminum-doped zinc tin oxide while retaining its low optical absorption. We found that the H2-plasma treatment performed at a substrate temperature of 50 °C reduces the resistivity of the films by 57% and increases the absorptance by only 2%. Additionally, the low substrate temperature delays the known formation of tin particles with the plasma and it allows the application of the process to temperature-sensitive substrates.

No abstract

No abstract