Ultraviolet emission from a diamond pn junction

We report the realization of an ultraviolet Light-emitting diode with the use of a diamond pn junction. The pn junction was formed from a boron-doped p-type diamond Layer and phosphorus-doped n-type diamond Layer grown epitaxially on the {111} surface of single crystalline diamond. The pn junction exhibited good diode characteristics, and at forward bias of about 20 volts strong ultraviolet Light emission at 235 nanometers was observed and was attributed to free exciton recombination.