Effective mass measurement in two-dimensional hole gas in strained $Si_{1-x-y}Ge_xC_y/ Si$(100) modulation doped heterostructures

A two-dimensional hole gas in the Si1-x-yGexCy channel on a Si(100) substrate has been demonstrated at temperatures from 0.3 to 300 K. The hole mobility decreases as more C is added. The hole effective mass has also been measured based on the analysis of the temperature dependence of Shubnikov-de Haas oscillations. It is found that the addition of C, up to 0.6%, does nor change the effective mass of holes in Si1-xGex. It suggests that the valence band structure of Si1-x-yGexCy is similar to that of Si1-xGex