Properties of zinc oxide films grown on sapphire substrates using high-temperature H2O generated by a catalytic reaction on platinum nanoparticles

Abstract

The authors investigated the characteristics of ZnO films grown on a-plane (11-20) sapphire substrates at 773–873 K using a reaction between dimethylzinc and high-temperature H2O generated by a catalytic reaction on Pt nanoparticles. The growth rate was 0.02–0.07 μm min−1. The largest electron mobility and the smallest residual carrier concentration for the ZnO films were 169 cm2 V−1 s−1 and 1.6 × 1017 cm−3, respectively. X-ray diffraction patterns for the ZnO films exhibited intense (0002) and (0004) peaks associated with ZnO (0001) planes. The minimum full width at half maximum of the ω-rocking curve for ZnO (0002) was less than 0.1°. In a ZnO film with a high electron mobility, no rotational domains were identified using a ZnO (10-10) ϕ scan. From secondary ion mass spectroscopy, a hydrogen concentration of 3 × 1018 cm−3 and a boron concentration of 2–5 × 1017 cm−3 were determined. These were identified as extrinsic donor impurities.