The material quality of the grown epitaxial layers was studied by (i) low temperature photoluminescence (LTPL) at 2 K with a frequency doubled Argon ion laser at 244 nm,and(ii) by high resolution X-ray diffraction (HRXRD) using a triple axis diffractometer equipped with a 4-bounce Ge(220) symmetrical optics using a 5 × 5 mm 2  X-ray slit opening (corresponding to a footprint of ∼5 × 16 mm 2  for the 4H-SiC(0004) peak) and 3-bounce Ge(220) symmetrical analyzer.