Published online by Cambridge University Press: 26 February 2011
4H-SiC single crystals have been fabricated on the seeds of 6H-type crystals by the vacuum-sublimation (modified Lely) method at a temperature of 2400 °C and under a pressure of 2–60 mbar in an argon atmosphere. Liquid phase epitaxy was attempted by using a dipping method with a 4H-SiC off-orientation substrate whose {0001} C-face varied toward the <1120> direction by 5 degrees. The polytype of the grown crystals was found to be the 4H-type through measurements of Raman scattering and photoluminescence. P-n junction diodes were epitaxially obtained on 4H-SiC substrates. Aluminum and nitrogen were doped as acceptors and donors, respectively. The LED emitted bluish-purple light with a high brightness of 2.2 mcd at a forward current of 20 mA. Other characteristics were as follows : 420–425 nm peak wavelength, 90 % color purity, and a light output of 4 μW.