Characterization of p–n structures grown by sublimation heteroepitaxy of 3C-SiC on 6H-SiC

A study on forward I–V characteristics of p–n structures grown by sublimation heteroepitaxy of 3C-SiC on 6H-SiC shows that about 90% of all the diodes can be placed in two groups. Current–voltage (I–V) characteristics of type I diodes are close to those of high-perfection p–n homostructures based on bulk 3C-SiC, with some indications of tunneling currents. I–V characteristics of type II diodes are close to those of p–n homostructures grown by epitaxial methods on single-crystal 6H-SiC substrates. Diodes of both types emit in the entire visible spectral range. The longer-wavelength emission is predominant in type I diodes, and shorter-wavelength emission in type II diodes. However, the main feature of the injection electroluminescence (IEL) is the qualitative similarity of the IEL spectra for diodes of both types. In particular, the IEL spectra of both diode types contain two bands (with hνmax≈2.3 and 2.9 eV), attributed to free exciton annihilation in 3C-SiC and 6H-SiC, respectively.