The free carrier density and mobility in n-type 4H-SiC substrates and epilayers were determined by accurately analysing the frequency shift and the full-shape of the longitudinal optic phonon-plasmon coupled(LOPC) modes,and compared with those determined by Hall-effect measurement and that provided by the vendors.The transport properties of thick and thin 4H-SiC epilayers grown in both vertical and horizontal reactors were also studied.The free carrier density ranges between 2×10 18 cm-3 and 8×10 18 cm-3 with a carrier mobility of 30-55 cm 2 /(V·s) for ntype 4H-SiC substrates and 1×10 16-3×10 16 cm-3 with mobility of 290-490 cm2 /(V·s) for both thick and thin 4H-SiC epilayers grown in a horizontal reactor,while thick 4H-SiC epilayers grown in vertical reactor have a slightly higher carrier concentration of around 8.1×10 16 cm-3 with mobility of 380 cm 2 /(V·s).It was shown that Raman spectroscopy is a potential technique for determining the transport properties of 4H-SiC wafers with the advantage of being able to probe very small volumes and also being non-destructive.This is especially useful for future mass production of 4H-SiC epi-wafers. The free carrier density and mobility in n-type 4H-SiC substrates and epilayers were determined by precisely analysing the frequency shift and the full-shape of the longitudinal optic phonon-plasmon coupled (LOPC) modes, and compared with those determined by Hall- effect measurement and that provided by the vendors. Transport properties of thick and thin 4H-SiC epilayers grown in both vertical and horizontal reactors were also studied. The free carrier density ranges between 2 × 10 18 cm -3 and 8 × 10 18 cm -3 with a carrier mobility of 30-55 cm 2 / (V · s) for ntype 4H-SiC substrates and 1 × 10 16-3 × 10 16 cm -3 with mobility of 290-490 cm 2 / (V · s) for both thick and thin 4H-SiC epilayers grown in a horizontal reactor, while thick 4H-SiC epilayers grown in vertical reactor have a slightly higher carrier concentration of around 8.1 × 10 16 cm -3 with a mobility of 380 cm 2 / (V · s) .It was shown that Raman spectroscopy is a potential technique for determining the transport properties of 4H-SiC wafers with the advantage of being able to probe very small volumes and also being non-destructive. This is especially useful for future mass production of 4H-SiC epi-wafers.