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 electrons we have observed an ODCR peak at a higher magnetic field, which is attributed 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 holes were determined as m(h perpendicular to) = (0.66+/-0.02)m(0) and m(h parallel to) = (1.75+/-0.02)m(0). The influence of the polaron coupling effect on the effective mass values in 4H SiC is discussed.