SiC blue LED's by liquid-phase epitaxy

Blue-light-emitting diodes of SiC were fabricated by liquid-phase epitaxy with a dipping technique, p-n junctions were obtained in the same growth run by dipping SiC substrates into a silicon melt in a graphite crucible. Nitrogen was used as donors and aluminum as acceptors. The p-layer of about 40 µm thick was grown on the substrate in the silicon melt with 2.5 at. % aluminum metal in flowing argon gas. Then nitrogen gas less than 0.01 vol.% was introduced to overcompensate aluminum acceptors and the n-layer of about 10 µm was grown. The carrier concentrations of the p- and n-layers were 2.3 × 10
¹⁸
and 5.2 × 10
¹⁸
cm
^-3
, respectively. Blue electroluminescence was observed in the forward direction. The luminescence is considered to include both the pair emission between nitrogen donors and aluminum acceptors and the recombination of free electrons with bound holes at acceptors. The external quantum efficiency of the electroluminescence was 1.0 × 10
^-5
photons/electron at room temperature.