Electrical and light-emitting properties of homoepitaxial diamond p-i-n junction

We have investigated the electrical and light-emitting characteristics of (001)-oriented homoepitaxial diamond p-i-n junction diodes with the boron-doped p-type, non-doped intrinsic, and phosphorus-doped n-type layers formed by applying an optimized homoepitaxial growth technique based on microwave plasma-enhanced chemical vapor deposition. High-performance p-i-n junction characteristics were confirmed from current-voltage and capacitance-voltage properties. A strong ultraviolet light emission at around 240 nm due to free exciton recombination was observed at a forward current of over 6 mA, while the broad visible light emission from deep levels was significantly suppressed compared to that of reported electroluminescence in diamond p-n junctions. It was elucidated that the excitonic emission intensity increases superlinearly for the current dependence and is stable even at the high temperature of 200 degrees C. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.