@article{RychkovGerhardKuznetsovetal.2018,
  author    = {Rychkov, Dmitry and Gerhard, Reimund and Kuznetsov, Alexey and Rychkov, Andrey},
  title     = {Influence of charge density on the trap energy spectrum in fluoroethylenepropylene copolymer films with chemically modified surfaces},
  series = {IEEE transactions on dielectrics and electrical insulation},
  volume    = {25},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  number    = {3},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1070-9878},
  doi       = {10.1109/TDEI.2018.007437},
  pages     = {840 -- 844},
  year      = {2018},
  abstract  = {Tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films were treated with titanium-tetrachloride vapor by means of molecular-layer deposition. The treatment leads to considerable improvements of the electret-charge stability on positively charged films. A slight improvement is also observed for negatively charged films. In line with our previous findings, we attribute the improvement in electret properties to the formation of deeper traps on the chemically modified polymer surfaces. Here, we investigate the influence of the charge density on electret stability of FEP films with modified surfaces. Trap-energy spectra obtained from thermally-stimulated-discharge measurements indicate that the charge stability on modified FEP films depends on how the surface traps are populated and on the availability of additional deeper traps.},
  language  = {en}
}
@article{RychkovGerhardIvanovetal.2012,
  author    = {Rychkov, Dmitry and Gerhard, Reimund and Ivanov, Vadim and Rychkov, Andrey},
  title     = {Enhanced electret charge stability on Polyethylene Films treated with Titanium-Tetrachloride vapor},
  series = {IEEE transactions on dielectrics and electrical insulation},
  volume    = {19},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  number    = {4},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1070-9878},
  pages     = {1305 -- 1311},
  year      = {2012},
  abstract  = {Low-density polyethylene (LDPE) films have been treated with titanium-tetrachloride vapor by means of the molecular-layer-deposition method. It is shown that such a treatment leads to a considerable improvement of the electret properties for both positively and negatively charged films. The temperature stability of the electret homo-charge has been increased by approximately 60 degrees C. At the same time, the temporal stability of charge is also considerably improved. Modified low-density polyethylene films show no "cross-over phenomenon" when charged to higher voltages. Thus, it is now possible to produce electrets from polyethylene films with high initial charge densities, but without a strongly reduced charge stability. The influence of a chemical treatment with titanium-tetrachloride vapor on charge injection from aluminum electrodes into polyethylene films was also investigated. It is found that the interface between an aluminum electrode and a modified LDPE surface layer has different injection properties for positive and negative charges. Electrons can be injected across the modified interface, whereas injection of holes is either very limited or non-existent.},
  language  = {en}
}