Gautam S K, Malik M, Jyotsna S and Poddar P
National Chemical Laboratory-CSIR, India
Posters & Accepted Abstracts: Res. Rev. J Mat. Sci
Oxide-semiconductor based heterojunction nanocomposites (HNCs) have garnered enormous research interest worldwide and exhibited progressively advanced features such as effective separation of photo generated electron hole pairs for their auspicious adoption in photovoltaic, photocatalytic and optoelectronic applications. Great emphasis has been paid to fulfill the objectives of HNCs by synthesizing nanocrystalline narrow band gap p-type copper oxide with wide band gap n-type zinc oxide using sol-gel technique. The structural, optical and electronic properties of developed HNCs were studied using X-ray diffraction, micro-Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), photo-luminescence spectroscopy and X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) techniques. Results revealed that Cu doping concentration upto 5% remains within the solubility limit of ZnO however, the higher Cudoping concentration leads to formation of ZnO-CuO HNCs. Cu-doping decreases ZnO band gap by introducing impurity energy levels and exhibits absorption in visible region of electromagnetic radiation. The crucial information of local electronic structures has been understood in terms of the hybridized electronic states and variation of valence band maxima with respect to Fermi level with increasing the Cu-doping in ZnO-CuO HNCs. The enhanced photocatalytic activities and efficient charge transfer mechanism in ZnO/CuO HNCs are rationalized and studied in terms of band gap tuning, energy band alignment and charge migration at ZnO/CuO heterojunction interfaces. Detailed results will be presented.