Hole effective masses in 4H SiC

Optically detected cyclotron resonance (ODCR) at X-band frequency (similar to 9.23 GHz) was used to study hole effective masses in 4H SiC. In addition to the known ODCR signal related to the cyclotron resonance (CR) of electr ons we have observed an ODCR peak at a higher magnetic field, which is attr ibuted to the CR of holes. In the vicinity of the maximum of the uppermost valence band, the constant energy surface can be considered as an ellipsoid with the principal axis along the c axis and the effective masses of the h oles were determined as m(h perpendicular to) = (0.66+/-0.02)m(0) and m(h p arallel to) = (1.75+/-0.02)m(0). The influence of the polaron coupling effe ct on the effective mass values in 4H SiC is discussed.