Zhang Haoze, Alanthattil Ayana, Webster Richard F, Zhang Dawei, Ghasemian Mohammad B, Venkataramana Rajendra B, Seidel Jan, Sharma Pankaj
School of Materials Science and Engineering, The University of New South Wales (UNSW) Sydney, Sydney, New South Wales 2052, Australia.
Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India.
ACS Nano. 2023 Sep 12;17(17):17148-17157. doi: 10.1021/acsnano.3c04937. Epub 2023 Sep 1.
Ferroelectrics possess a spontaneous polarization that is switchable by an electric field and is critical for the development of low-energy nanoelectronics and neuromorphic applications. However, apart from a few recent developments, the realization of switchable polarization in metal oxides with simpler structures has been a major challenge. Here, we demonstrate the presence of robust switchable polarization at the level of a single nanocrystallite in magnesium-doped zinc oxide thin films with polar wurtzite crystal structures. Using a combination of high-resolution scanning probe microscopy and spectroscopic techniques, voltage control of the polarization and the coupled electronic transport behavior revealing a giant resistance change of approximately 10000% is unveiled. Time- and frequency-resolved nanoscale measurements provide key insights into the polarization phenomenon and a 9-fold increase in the effective longitudinal piezoelectric coefficient. Our work thus constitutes a crucial step toward validating nanoscale ferroelectricity in polar wurtzites for use in advanced nanoelectronics and memory applications.
铁电体具有可通过电场切换的自发极化，这对于低能耗纳米电子学和神经形态应用的发展至关重要。然而，除了最近的一些进展外，在结构更简单的金属氧化物中实现可切换极化一直是一项重大挑战。在此，我们证明了具有极性纤锌矿晶体结构的掺镁氧化锌薄膜在单个纳米微晶水平上存在强大的可切换极化。通过结合高分辨率扫描探针显微镜和光谱技术，揭示了极化的电压控制以及耦合电子输运行为，显示出约10000%的巨大电阻变化。时间分辨和频率分辨的纳米级测量为极化现象提供了关键见解，并使有效纵向压电系数提高了9倍。因此，我们的工作是朝着验证极性纤锌矿中的纳米级铁电性以用于先进纳米电子学和存储器应用迈出的关键一步。
