Electrical and optical characterizations of (001)-oriented homoepitaxial diamond p–n junction

We have succeeded in fabricating (001)-oriented diamond p–n junctions with clear diode characteristics and conformed ultraviolet (UV) light emission by current-injection at room temperature. As p–n junctions, a phosphorus doped n-type layer was formed on (001)-oriented boron doped p-type one by applying an optimized homoepitaxial growth technique based on microwave plasma-enhanced chemical vapor deposition. Current–voltage characteristics showed a rectification ratio of 103 at ± 30 V at room temperature. The existence of the space-charge layer at the vicinity of the p–n junction was confirmed from capacitance–voltage (C–V) characteristics. From C− 2–V characteristics at 773 K, the built-in potential was estimated as approximately 4.7 V. A strong UV light emission at 235 nm due to free exciton recombination with transverse-optical phonon was observed at forward current over 36 mA in these p–n junctions.