Contactless electroreflectance of GaN0.025As0.975−xSbx∕GaAs quantum wells with high Sb content (0.27⩽x⩽0.33): The determination of band gap discontinuity

Abstract

Ga N 0.025 As 0.975 − x Sb x ∕ Ga As quantum wells (QWs) with x=0.27 and x=0.33 were investigated by contactless electroreflectance (CER) spectroscopy. CER features related to optical transitions between the ground and excited states were clearly observed, indicating that these QWs have type-I structures. By matching the QW transition energies with those obtained from theoretical calculations performed within the electron effective mass approximation the conduction band offset in these QWs is found to be close to 40%. The resulting conduction band discontinuities were found to be ∼200 and ∼150meV for the QWs with x=0.27 and x=0.33, respectively.