The reverse leakage current in n -type nanodiamond film/ p -type silicon wafer heterojunction diodes is examined as a function of the film conductivity. We observe that as the delocalization of carriers in the films becomes stronger, the leakage current becomes larger (from 10-3 to 101 A cm-2). The major leakage source is attributed to the minority carriers from the π defect bands introduced by sp2 carbon. Both a current injection barrier and a dielectric barrier at the interface are found to be small (∼0.6 eV). The simultaneous reduction in leakage current and turn-on voltage for low-loss diodes needs optimization of the interfacial valence band connection.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)