We fabricated diamond p-i-n diodes with homoepitaxially grown films on a heteroepitaxial diamond (001) substrate produced with diamond films grown on iridium (Ir). We applied our state-of-the-art techniques on single crystal diamond-based electronic devices. The current-voltage characteristics of the p-i-n diodes showed good rectification properties. Under forward current operation, the diode showed both free exciton and defect-related luminescence. When the forward current increased, integrated intensity of defect-related luminescence increased sub-linearly, while that of free exciton luminescence increased super-linearly. This remarkable trend is the same as that observed in a p-i-n diode fabricated with homoepitaxially grown films on the conventional high-pressure and high-temperature synthesized diamond single-crystal substrates. The results obtained in this paper indicate a sufficient potential of the heteroepitaxial diamond substrates grown on Ir for future diamond-based electronic devices.

The switching characteristics of a diamond p+–i–n+ diode have been investigated to highlight the reverse recovery phenomenon, which is a consequence of the base conductivity modulation. The electrical transport within a diamond p+–i–n+ diode is still unclear, and the effectiveness of the base conductivity modulation remains the main concern. The measured turn-off waveforms of the diamond p+–i–n+ diode showed reverse recovery, thus confirming its bipolar nature. The diamond p+–i–n+ diode exhibits soft recovery and very fast switching behaviors (the recovery time was less than 200 ns). Moreover, according to the switching conditions, the reverse recovery in the diamond p+–i–n+ diode may induce a turn-off failure, which is ascribed to the well-known dynamic avalanche breakdown.