<title>Evaluation of the band offsets of GaAs/GaInP multilayers by electroreflectance</title>

We report the first band offset measurement of GaAs/Ga_0.51In_0.49P multiquantum wells and superlattices by electrolyte electroreflectance spectroscopy. The conduction and valence band discontinuities (Delta) E_c equals 159 +/- 4 meV and (Delta) E_v equals 388 +/- 6 meV have been measured. The values found for the conduction band, heavy-hole and light-hole masses in the GaInP barriers and GaAs wells and for the split-off well mass are in excellent agreement with the literature. The intraband, intersubband transition energies, which are important for III - V infrared detection devices, also were directly measured.