dc sputtered indium-tin-oxide films have been excimer laser irradiated at subablation threshold fluences (<510 mJ/cm2). Optical characterization of irradiated products has been performed aiming at resolving the finer structure appearing in the IR–visible absorption spectra, as a function of laser fluence, and assigning such features to specific electronic defects which are produced upon irradiation. Four individual Gaussian-like contributions to absorption spectra are identified at 0.7, 1.0, 1.6, and 2.6 eV, the intensity of which is observed to vary with fluence. Being absent in the original films and emerging in optical spectra at fluences exceeding 300 mJ/cm2, the 2.6 eV contribution is most characteristic to excimer laser processing and is responsible for the darkening of the film. Thermal model calculations reveal that such defects are produced only upon melting and fast resolidification of the film. The evolution of the chemistry actually taking place in the film upon irradiation is followed by x-ray photoelectron spectroscopic analysis. A chemical approach to the production of such defects is proposed in which oxygen displacement in the atomic matrix leads to the formation of neutral ternary complexes of the type SnIn2O4.

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Au nanoparticles are commonly used as seeds for epitaxial growth of III–V semiconductor nanowires. However, the interaction between Au and In-containing III–V materials makes it difficult to control the growth of more complex nanowire structures in materials such as InAs. Here we report the growth of InAs nanowires and branched nanotrees using Au and Au–In nanoparticles. We show that the initial composition of the particle does not affect the morphology of the first-generation nanowires, nor does it affect the final composition of the particle after growth. However, when the Au–In particles were used to seed a second generation of nanowires, producing nanotrees, the branches exhibited a 2–3 times higher growth rate and more regular shape than those seeded by pure Au particles. This result is attributed to the decreased interaction between the seed particle and the trunk nanowires when Au–In particles are used. Thus the incorporation of In into the seed particle during particle production allows for modification of the particle–wire interaction.

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