Features of electrical charge transfer in porous silicon

Thermostimulated depolarization (TSD) spectra of porous silicon (PS) in the range of temperatures 77-450 K were investigated. Several wide bands of TSD current with different values referred to different types of PS charged defects were discovered. A comparative investigation of TSD spectra of PS layers and films of dioxide silicon on the silicon substrates was carried out. Low-temperature (77-300 K) parts of these spectra were identified. Activation energies of defects and capture centers of PS were calculated. Low-temperature defects were identified as hydrogen oxygen type ions. The influence of infrared- and X-rays of PS on TSD spectra was determined. An energy scheme for charge transport in PS based on changes in TSD spectra was proposed. Temperature changes of planar current voltage characteristics and frequency dispersion of the capacity of porous silicon silicon substrate heterostructures were investigated. The anomalous character of dependencies is explained by special features of ion transfer in PS. (Author)