Abstract
We have succeeded in fabricating (001)-oriented diamond p–n junctions with good diode characteristics and realized 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 micro-wave plasma-enhanced chemical vapor deposition. Current–voltage characteristics showed a rectification ratio of 106 at ±30 V at room temperature. The existence of the space-charge layer through the p–n junction was confirmed from capacitance–voltage characteristics. A strong UV light emission at 235 nm was observed at forward current over 20 mA and is attributed to free exciton recombination.