High-temperature diamond p-n junction: B-doped homoepitaxial layer on N-doped substrate

Boron-doped homoepitaxial layers have been selectively grown on synthetic type Ib substrates of (100) cut. Ohmic contacts were formed by evaporating a Mo/Pt/Au sandwich and subsequent annealing at 950°C for h. Current–voltage characteristics of diode type could be taken in vacuum in the temperature range 360–900 °C. Green light emission due to electroluminescence was observed from the junction area showing a maximum at a wavelength of 534 nm corresponding to a photon energy of 2.32 eV. The normalized emission spectrum was measured over the temperature range 320–440 °C with the device in air and was found independent of temperature and boron concentration.