A molecular approach to Cu doped ZnO nanorods with tunable dopant content

A novel molecular approach to the synthesis of polycrystalline Cu-doped ZnO rod-like nanostructures with variable concentrations of introduced copper ions in ZnO host matrix is presented. Spectroscopic (PLS, variable temperature XRD, XPS, ELNES, HERFD) and microscopic (HRTEM) analysis methods reveal the +II oxidation state of the lattice incorporated Cu ions. Photoluminescence spectra show a systematic narrowing (tuning) of the band gap depending on the amount of Cu(II) doping. The advantage of the template assembly of doped ZnO nanorods is that it offers general access to doped oxide structures under moderate thermal conditions. The doping content of the host structure can be individually tuned by the stoichiometric ratio of the molecular precursor complex of the host metal oxide and the molecular precursor complex of the dopant, Di-aquo-bis[2-(methoxyimino)-propanoato]zinc(II) 1 and -copper(II) 2. Moreover, these keto-dioximato complexes are accessible for a number of transition metal and lanthanide elements, thus allowing this synthetic approach to be expanded into a variety of doped 1D metal oxide structures

Interrelation between Chemical, Electronic, and Charge Transport Properties of Solution-Processed Indium–Zinc Oxide Semiconductor Thin Films

<i>Solution-processed</i> metal oxide semiconductors are of high interest for the preparation of high-mobility transparent metal oxide (TMO) semiconductor thin films and thin film transistors (TFTs). It has been shown that the charge transport properties of indium–zinc oxide (IZO) thin films from molecular precursor solutions depend strongly on the preparation conditions, in particular on the precursor conversion temperature <i>T</i>_pc and, to some surprise, also on the concentration of the precursor solution. Therefore, the chemical and the electronic structure of solution-processed IZO thin films have been studied in detail with X-ray photoelectron spectroscopy (XPS) under systematic variation of <i>T</i>_pc and the concentration of the precursor solution. A distinct spectral feature is observed in the valence band spectra close to the Fermi level at <i>E</i>_B = 0.45 eV binding energy which correlates with the trends in the sheet resistivity, the field effect mobility μ_FE, and the optical gap <i>E</i>_g^opt from four-point-probe (4PP), TFT, and UV–vis measurements, respectively. A comprehensive model of the interrelation between the conditions during solution-processing, the chemical and electronic structure, and the charge transport properties is developed

Interrelation between Chemical, Electronic, and Charge Transport Properties of Solution-Processed Indium–Zinc Oxide Semiconductor Thin Films

Solution-processed metal oxide semiconductors are of high interest for the preparation of high-mobility transparent metal oxide (TMO) semiconductor thin films and thin film transistors (TFTs). It has been shown that the charge transport properties of indium-zinc oxide (IZO) thin films from molecular precursor solutions depend strongly on the preparation conditions, in particular on the precursor conversion temperature T-pc and, to some surprise, also on the concentration of the precursor solution. Therefore, the chemical and the electronic structure of solution-processed IZO thin films have been studied in detail with Xray photoelectron spectroscopy (XPS) under systematic variation of Tpc and the concentration of the precursor solution. A distinct spectral feature is observed in the valence band spectra close to the Fermi level at E-B = 0.45 eV binding energy which correlates with the trends in the sheet resistivity, the field effect mobility mu(FE), and the optical gap E-g(opt) from four-point-probe (4PP), TFT, and UV-vis measurements, respectively. A comprehensive model of the interrelation between the conditions during solution-processing, the chemical and electronic structure, and the charge transport properties is developed