Direct measurement of electrostatic fields within the Zernike electrostatic phase plate using single 155 nm Teflon nanoparticle attached to the pillar-shaped atomic force microscope tip. - Chang, Joe-Ming; Wu, Wei-Jung; Chang, Wei-Yu; Chen, Fu-Rong; Tseng, Fan-Gang (Journal of Vacuum Science & Technology: Part B-Nanotechnology & Microelectronics, 2019)