Investigation of optical and electronic properties of selected transition metal oxides

Abstract

Transition metal oxides (TMO) belong to an interesting group of oxide materials with wide varieties of optical, electrical and magnetic properties. Many of these properties are strongly controlled by number of electrons in d-orbitals and also significantly depend on various defects such as; vacancies, dislocations and stacking faults etc. General formulae of parent TMO is MO2n±1, where, M represents the transition metal ions and n is an integer. The other important group is perovskite-based transition metal oxides with general formula AMO3 (A is either a divalent alkali metal or trivalent rare earth element) has also attracted the attention of scientific community and been investigated by researchers worldwide due to their potential application in electronic, optical and memory based devices. In order to investigate the electronic structure of TMO, various experimental techniques such as valence band spectroscopy, x-ray photoelectron spectroscopy, and photoluminescence spectroscopy are already being used by many research groups[1–3]. In addition to all these techniques, the optical absorption spectroscopy (in UV-VIS region) is also known to provide the information about the electronic structure, specifically, near band edge[1–8], which is essentially believed to control the various properties of TMO.