UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2015 Meeting


Section: Solid State Physics and Materials Science


Title:
Improvement of the detection features for infrared detectors based on ferroelectric thin films


Authors:
M. BOTEA (1,2), A.G. BONI (1,2), C. CHIRILA (2), A. IUGA (2), V. STANCU (2), L. PINTILIE (2)


Affiliation:
1) University of Bucharest, Faculty of Physics, Magurele 077125, Romania

2) National Institute of Materials Physics, Atomistilor 105bis, Magurele, Ilfov, 77125, Romania



E-mail
mihaela.botea@infim.ro


Keywords:
ferroelectric, thin films, pyroelectric, substrate, detectors


Abstract:
Using ferroelectric materials for IR detection has many advantages such as: low prices, simple manufacturing technology, operation at room temperature, wide spectral range usage and good sensitivity. Therefore, researchers are looking to discover new materials and methods to improve these properties. Novel technologies require replacement of bulk ferroelectric materials with thin films. The development of the physical deposition techniques allow controlling the quality of both the structure and the interface, making possible to obtain high quality epilayers. High crystallinity and optimal ferroelectric domain orientation ensure desired physical properties, including pyroelectric ones. The PZT films 20/80 were obtained by two methods - sol gel and pulsed laser deposition - on different substrates (platinium silicon and strontium titanate) in order to investigate the pyroelectric effect. The structural and morphological properties of the films were examinated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM), and their ferroelectricity was tested by performing capacitance-voltage (C-V) and hysteresis measurements at room temperature. The pyroelectric measurements on the PZT thin films were performed with modulated light from an 800 nm laser diode coupled with a mechanical chopper having variable frequency. The pyroelectric signal was collected in the voltage mode, with a field effect transistor, and recorded with a lock-in amplifier. Superior detection characteristics can be obtained through the choice of an adequate material for the active layer, through the choice of the substrate or as a conseqence of induced phenomena by simultaneously ilumination with ultraviolet and infrared radiation.


References:

1.Applied Physics Letters 105,132901(2014), L. Pintilie, M. Botea and A.Iuga

2.Applied Physics Letters 86, 022907(2005) M. Es-Souni et al.

3.Applied Physics Letters 103,232902(2013) M. Botea, A.Iuga, and L. Pintilie

4.Integrated Ferroelectrics, Vol.25, 135-147 (1999), R. P. Godfrey et al.



Acknowledgement:
I wish to acknowledge the project POSDRU/159/1.5/S/137750, “Project Doctoral and Postdoctoral programs support for increased competitiveness in Exact Sciences research” cofinanced by the European Social Found within the Sectorial Operational Program Human Resources Development 2007-2013.