Research Projects

Ferroelectric (FE) memories have been a potential candidate for universal memories due to their low power consumption. However, the disappearance of ferroelectricity (FEy) with device miniaturization has made these materials unsuitable for the microelectronics industry. The discovery of FEy in doped hafnia-based, Si compatible, simple fluorite oxides in 2011 led to a resurgence of FEs. The origin of this FEy is debated, but defects like oxygen vacancies (Vo) play a crucial role in FE switching. The researchers will investigate the fundamental origins of FEy and assess oxygen conducting centrosymmetric fluorites like yttria stabilized zirconia. They will synthesize thin films epitaxially on Si using pulsed laser deposition and study them through structure-FEy-defect correlation studies using state-of-the-art techniques. The lessons learned will be used to propose materials selection guidelines for new types of Si-friendly FEy that go beyond fluorites. From a device perspective, they will fabricate FE tunnel junction devices through ultrathin layers, aiming to enhance memory endurance and retention. Defect complexes are shown to give giant electromechanical effects in doped CeO2, sister compounds of hafnia. They will also study various doped ceria systems to propose guidelines for defect complex-EM property correlations. The researchers aim to create a single system with both large extrinsic FEy and EM response, similar to PZT. They will fabricate actuators for lower frequency from pseudo piezoelectric systems and assess them as Pb-free alternatives for Micro/nanoelectromechanical Systems (M/NEMS).