Content area
Full Text
J Mater Sci: Mater Electron (2014) 25:25072515 DOI 10.1007/s10854-014-1903-5
Europium incorporated barium titanate thin lms for optical applications
L. V. Maneeshya S. Sujatha Lekshmy
P. V. Thomas K. Joy
Received: 11 February 2014 / Accepted: 25 March 2014 / Published online: 2 April 2014 Springer Science+Business Media New York 2014
Abstract BaTiO3:Eu (BT:Eu) thin lms were deposited onto quartz substrates by RF magnetron sputtering. The effect on structural, morphological, optical and photoluminescence (PL) properties in the lms with different Eu concentrations (05 wt%) were investigated. The X-ray diffraction (XRD) pattern of the undoped BT thin lm revealed a tetragonal (T) phase with orientations along (101) plane. From XRD pattern, the crystallinity of the lms increased with increase in Eu concentration. The SEM images revealed that the lms exhibited tetragonal shape, crack free and good adherence to the substrate. Atomic force microscopy studies showed an increase of grain growth with doping concentration. The rms roughness value increased with increase in Eu concentration and the lm surface revealed positive skewness and high value of kurtosis which make them suitable for tribological applications. X-ray photoelectron spectroscopy revealed the presence of barium, titanium, europium and oxygen in BT:Eu lm. An average transmittance of[80 % (in visible region) was observed for all the lms. Optical band gap of
Eu doped BT lms decreased from 3.86 to 3.53 eV. Such lms with optical properties such as high transparency, decrease in band gap and high refractive index are suitable for optoelectronic applications. PL properties showed a sharp line at 625 nm and a broad line at 552 nm due to europium (Eu3?) transitions. PL phenomena were observed, owing to the electronic structure of Eu3? ions as well as BT nanocrystallites in the lms. The sharp and
intense red luminescence is useful for photoelectric devices and optical communications.
1 Introduction
The perovskites have considerable attention and constitute one of the most important classes of mixed oxides. These oxides are attractive as a host material for rare earth doping [1, 2]. Luminescent rare earth doped materials are extensively studied because of their potential application in photonic devices and next generation at panel displays. It presents various applications owing to their physical properties and has been extensively studied as candidates for electro-optical devices. The perovskites...