<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liang Chen</style></author><author><style face="normal" font="default" size="100%">Liang, Zhongxin</style></author><author><style face="normal" font="default" size="100%">Shao, Shixuan</style></author><author><style face="normal" font="default" size="100%">Huang, Qianqian</style></author><author><style face="normal" font="default" size="100%">Tang, Kechao</style></author><author><style face="normal" font="default" size="100%">Ru HUANG</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">First direct observation of the built-in electric field and oxygen vacancy migration in ferroelectric Hf0.5Zr0.5O2 film during electrical cycling</style></title><secondary-title><style face="normal" font="default" size="100%">Nanoscale</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2023</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1039/D2NR06582G</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">The Royal Society of Chemistry</style></publisher><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">7014-7022</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The wake-up and fatigue effects exhibited by ferroelectric hafnium oxide (HfO2) during electrical cycling are two of the most significant obstacles limiting its development and application. Despite a mainstream theory relating these phenomena to the migration of oxygen vacancies and the evolution of the built-in field, no supportive experimental observations from a nanoscale perspective have been reported so far. By combining differential phase contrast scanning transmission electron microscopy (DPC-STEM) and energy dispersive spectroscopy (EDS) analysis, we directly observe the migration of oxygen vacancies and the evolution of the built-in field in ferroelectric HfO2 for the first time. These solid results indicate that the wake-up effect is caused by the homogenization of oxygen vacancy distribution and weakening of the vertical built-in field whereas the fatigue effect is related to charge injection and transverse local electric field enhancement. In addition, using a low-amplitude electrical cycling scheme, we exclude field-induced phase transition from the root cause of the wake-up and fatigue in Hf0.5Zr0.5O2. With direct experimental evidence, this work clarifies the core mechanism of the wake-up and fatigue effects, which is important for the optimization of ferroelectric memory devices.</style></abstract></record></records></xml>