Ni-Alloyed Copper Iodide Thin Films: Microstructural Features and Functional Performance

To tailor electrical properties of often degenerate pristine CuI, Ni is introduced asalloy constituent. Cosputtering in a reactive, but also in an inert atmosphere aswell as pulsed laser deposition (PLD), is used to grow Nix Cu 1 x I thin films. TheNi content within the alloy thin films is systematically varied for different growthtechniques and growth conditions. A solubility limit is evidenced by an additionalNiI 2ðH2 OÞ6 phase for Ni contents x ≥ 0.31, observed in X-Ray diffraction andatomic force microscopy by a change in surface morphology. Furthermore,metallic, nanoscaled nickel clusters, revealed by X-Ray photoelectron spectros-copy and high-resolution transmission electron microscopy (HRTEM), underpina solubility limit of Ni in CuI. Although no reduction of charge carrier density isobserved with increasing Ni content, a dilute magnetic behavior of the thin filmsis observed in vibrating sample magnetometry. Further, independent of thedeposition technique, unique multilayer features are observed in HRTEMmeasurements for thin films of a cation composition of x ≈ 0.06. Opposite toprevious claims, no transition to n-type behavior was observed, which was alsoconfirmed by density functional theory calculations of the alloy system.