Nano scale surface characterization of muscovite mica after contact electrification (CE) using tapping mode Kelvin force microscopy

Contact electrification (CE) between an n-type Si Atomic Force Microscope tip and a disk of a muscovite mica was demonstrated and characterized in the nanoscopic level using 300kHz tapping mode of Kevin Force Microscope (KFM). Band diagram of AFM tip and mica sample which can be modeled as a semiconductor insulator interface has showed that CE on the surface of mica can be heavily influenced by application of DC bias voltage on the n-type Si tip greater than ±1 volt. Quantum charge tunneling and back tunneling was indirectly observed when the AFM tip amplitude set point was varied from 10nm to 40nm and when DC voltage bias was varied from ±1 volt to ±2 volt manifested by the surface potential sign reversal. Furthermore, it was shown that after CE for both cleaved mica at {001} plane and rubbed mica by cotton Q−tip, surface potential relaxation happened due to oxidation of mica after exposure to the laboratory as indicated by XPS (X-ray photoelectron spectroscopy) spectrum of KCO3. Further research on its energy band interface and CE characteristics has potential applications in triboelectric self-powering sensors