MOCVD growth of Cd(Zn)O thin films and isolated nanoparticle arrays on (0 0 1) GaAs substrates

• Cd 1−x Zn x O was grown directly on GaAs by atmospheric-pressure MOCVD • Two morphologies were achieved: isolated nanoparticles and thin films. • Growth follows Volmer-Weber mechanism with controllable nucleation density. • Effects of Zn incorporation on morphological and structural properties were analysed. • Results enable mid-IR plasmonic integration on functional substrates. In this work, Cd 1−x Zn x O crystals were grown by atmospheric pressure metal–organic chemical vapour deposition (MOCVD) on semi-insulating GaAs (0 0 1) substrates. The growth followed a Volmer-Weber mechanism, enabling the formation of two distinct morphologies, quasi-hemispherical nanoparticles and polycrystalline thin films, capable of supporting localized plasmon resonances (LPRs) and surface plasmon polaritons (SPPs), respectively. Growth conditions were optimized through systematic parametric studies evaluating the effects of substrate temperature, precursor flow rates, deposition time, and substrate position within the reactor. Additionally, a two-step growth was proposed for improving flatness and reducing layer thickness in thin films. These results provide a robust growth strategy for directly integrating Cd 1−x Zn x O onto GaAs, one of the most relevant platforms in IR optoelectronics, paving the way for high-performance plasmonic devices operating in the mid-IR.