Electron effective mass and phonon modes in GaAs incorporating boron and indium

The strain-free boron- and indium-containing GaAs compounds are promising candidates for III-V semiconductor solar cell absorber materials with lattice match to GaAs, for which experimental data of the electronic band structure are widely unknown. For nondegenerate, silicon-doped, n -type B0.03 In0.06 Ga0.91 As with band-gap energy of 1.36 eV, determined by near-infrared ellipsometry, a strong increase of the electron effective mass of 44% in B0.03 In0.06 Ga0.91 As compared to In0.06 Ga0.94 As is obtained from far-infrared magneto-optic generalized ellipsometry studies. The authors thereby obtain the vibrational lattice mode behavior. For BAs, an experimentally obscure compound, the curvature of the -point conduction band thus extrapolates to the free electron mass.