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arXiv · 1702.04791

Room-temperature relaxor ferroelectricity and photovoltaic effects in SnTiOx/Si thin film heterostructures

Radhe Agarwal·Yogesh Sharma·Siliang Chang·Krishna Pitike·Changhee Sohn·Serge M. Nakhmanson·Christos G. Takoudis·Ho Nyung Lee·James F. Scott·Ram S. Katiyar·Seungbum Hong
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Abstract

We have studied ferroelectricity and photovoltaic effects in atomic layer deposited (ALD) 40-nm thick SnTiO$_{x}$ films deposited directly onto p-type (001)Si substrate. These films showed well-saturated, square and repeatable hysteresis loops with remnant polarization of 1.5 $μ$C/cm$^{2}$ at room temperature, as detected by out-of-plane polarization versus electric field (P-E) and field cycling measurements. A photo-induced enhancement in ferroelectricity was also observed as the spontaneous polarization increased under white-light illumination. The ferroelectricity exhibits relaxor characteristics with dielectric peak shifting from ca. T = 600 K at f = 1 MHz to ca. 500 K at 100 Hz. Moreover, our films showed ferroelectric photovoltaic behavior under the illumination of a wide spectrum of light, from visible to ultraviolet regions. A combination of experiment and theoretical calculation provided optical band gap of SnTiO$_{x}$ films which lies in the visible range of white light spectra. Our study leads a way to develop green ferroelectric SnTiO$_{x}$ thin films, which are compatible to semiconducting processes, and can be used for various ferroelectric and dielectric applications.

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Radhe Agarwal, Yogesh Sharma, Siliang Chang, Krishna Pitike, Changhee Sohn, Serge M. Nakhmanson, Christos G. Takoudis, Ho Nyung Lee, James F. Scott, Ram S. Katiyar, Seungbum Hong. 2017-02-15. Room-temperature relaxor ferroelectricity and photovoltaic effects in SnTiOx/Si thin film heterostructures. https://doi.org/10.1103/physrevb.97.054109

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