Features of electrical charge transfer in porous silicon

Abstract

The 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. Comparative investigation of TSD spectra of PS layers and films of dioxide silicon on the silicon substrates were carried out. There was fixed the identification of low-temperature (77 - 300 K) parts of these spectra. Activation energies of defects and capture centers of PS were calculated. Low-temperature defects were identified as hydrogen - oxygen type ions. Infrared- and x-rays influence of PS on TSD spectra were fixed. An energy scheme of charge transport in PS based on changes in TSD spectra were 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.