Abstract
Thick anodic oxide films were formed in 15wt% H2SO4 bath and their electrical properties were investigated in order to clarify the effects of electrical and structural imperfections such as impurities, vacancies, and micro-pores.
The following results were obtained:
(1) Absorption currents having long relaxation times were observed, which suggested the presence of many traps in the films.
(2) The presence of traps was confirmed by measuring the detrapping currents by light irradiation during discharging process.
(3) The I-V characteristics of the films were expressed by the equation I=kVn (n=2), which indicates that the electrical conduction mechanism of the films is controlled by only one kind of carrier current limited by the space charge in the case of shallow trap states.
(4) The photo-quenched currents as well as the photo-induced currents were also found by measuring the photo-electric effects of the films.
