Invisible Surface Charge Pattern on Inorganic Electrets

Fei Wang, Ole Hansen

Research output: Contribution to journalJournal articleResearchpeer-review


We propose an easy method to pattern the surface charge of ${\rm SiO}_{2}$ electrets without patterning the dielectric layer. By eliminating the use of metal guard electrodes, both the charge efficiency and the surface charge stability in humid environments improve. We apply the concept to a vibrational energy harvesting device, where a power output of 3 $\mu{\rm W}$ is successfully harvested at a low acceleration of 0.05 g and a resonant frequency of 414 Hz. No decay of the power output can be observed in a RH95% humidity test, which shows that the surface charge is stable and this is promising for application in harsh environments.
Original languageEnglish
JournalI E E E Electron Device Letters
Issue number8
Pages (from-to)1047-1049
Publication statusPublished - 2013


  • Charge stability
  • Electret
  • Energy harvesting
  • Microelectromechanical system (MEMS)

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