Photomodulation study of partially s t r a i n ed I n xG a, -xAs I aye r s

Photomodulation techniques have been used to study the fundamental transitions of partially strained In,Ga,,As/GaAs (x = 0.07 and 0.16) epiiayers. The strain-induced splitting of the valence band was observed. The identification of the split valence bands was confirmed using linearly polarized photoreflectance under a totai internal refiectlon mode. The temperature dependence of two bandgap energies E,,, (heavy-hole band) and E,, (light-hole band) was studied over a temperature range from 15 to 300 K. The parameters that describe the temperature dependence of E,, and E,, as well as the broadening function are evaluated.