Event Details

Cooperative effect of oxygen-⁠vacancy-⁠rich layer and ferroelectric polarization on photovoltaic properties in BiFeO3 thin film capacitors

  • 2017-03-02
  • Pranab Biswas (PH14D012)

The mass production of ferroelectric random access memories has suffered from oxygen vacancy (VO••) related problems, such as domain clamping [1] fatigue, [2,3] and imprint phenomena, 4] which lead to a degradation of long-⁠term device reliability. Domain clamping causedomains to resist from switching and is known to cause significant problems in ferroelectric memories and iezoelectric devices. Fatigue refers to the gradual reduction of switchable polarization on cyclic alternating voltage pulses. Similarly, Imprint is described simply as preference of a certain polarization state over the other, causing failure in data storage devices. The accumulation of VO•• at a specific interface or boundary has traditionally been regarded to exert a negative influence on the ferroelectric properties. Despite all these negative effect of oxygen vacancy in ferroelectric devices, according to the report published by Matsuo et al. in 2016, the combined effect of oxygen vacancy layer and ferroelectric polarization can enhance photovoltaic properties significantly.5 In this talk I will be discussing about the strong interaction between the oxygen vacancy and ferroelectric polarization. I will also be discussing about the possible reasons for the oxygen layer to form at the bottom interface and its positive impact on photovoltaic effect.