Valence band structures of heavily doped strained GexSi1−x layers

Valence‐band structure and density‐of‐state (DOS) effective mass are calculated for heavily p‐type‐doped Si and strained GexSi1−x layers grown on (100) Si. At low doping values calculations have been made by earlier authors and the results agree with the published values of DOS mass by these authors. The Fermi energy EF measured from the valence‐band edge has been calculated using our values of DOS effective mass. At 1020 cm−3 doping level the value is 77.3 meV compared with 80 meV determined from luminescence experiments. The value of EF obtained by using the normally accepted value of 0.57 for the hole effective mass in Si is more than the experimental value by a factor about 2, i.e., the calculations reduce the discrepancy from 100% to less than 4%. The effective barrier height of (p+‐Ge0.42Si0.58)/(p‐Si) internal photoemission photo detector has also been calculated using our calculated value of the DOS hole mass. The calculated value is in reasonable agreement with the experimental value. The values ...