Direct determination of electron effective mass in GaNAs/GaAs quantum wells

Electron effective mass (me*) in GaNxAs1−x/GaAs quantum wells (QWs) is investigated by the optically detected cyclotron resonance technique. The me* values of 0.12m0 and 0.19m0 are directly determined for the 70-Å-thick QWs with N composition of 1.2% and 2.0%, respectively. This sizable increase in the electron effective mass is consistent with the earlier theoretical predictions based on the strong interaction of the lowest conduction band states with the upper lying band states or impurity band induced by the incorporation of N.