I─V characteristics of Bi4Ge3O12─Mn crystals in the unipolar injection mode

Abstract

Current-voltage relations in Bi4Ge3O12 ─ Mn crystals were measured under the conditions of unipolar injection of charge carriers. The characteristics obtained for electrons and holes are different. I-V curves in the case of electron injection contain ohmic, quadratic regions and regions of a sharp increase in current. This indicates the formation of a space charge enriched in electrons. The values of conductivity, effective drift mobility, and electron concentration calculated at different temperatures are close to the values obtained for pure crystals. In the case of hole injection I-V curves are characterized by the presence of sublinear regions. It is assumed that injection of the holes causes the formation of a space charge layer depleted in electrons due to the recombination. It is shown that doping with manganese does not change the nature of conductivity in bismuth germanate crystals and strongly affects the recombination processes.

Coloring of Bi4Ge3O12 – Mn crystals induced by electric field

“…It was shown in [9] that in BGO-Mn crystals, a manganese impurity takes part in the recombination process. This is also confirmed by I -V relations measured on BGO-Mn samples in the mode of the unipolar injection [10].…”

“…Ag or In-Ga were chosen as the metal of the injection electrode. In order to avoid double injection of charge carriers, a thin layer of silicate glass (Na2SiO3) was applied between the sample and the electrode on the other side of the sample similarly to the experiments described in [7,10]. The electric field (3 kV/cm) was applied at 600 K during 1 h. After cooling of the sample the electrodes were removed and optical transmittance of the samples was measured.…”