Properties of GaAsN/GaAs quantum wells studied by optical detection of cyclotron resonance

Effective masses and carrier recombination in GaNAs/GaAs quantum wells (QWs) with nitrogen composition up to 4.5%, have been studied by optical detection of cyclotron resonance (ODCR). When monitoring the PL emissions under the conditions of above-GaAs barrier excitation, the ODCR spectrum is dominated by the electron CR in GaAs with an effective mass value 0.066m0. The ODCR mechanism is discussed in terms of hot carrier effects, resulting in a reduced carrier recombination in GaAs and an enhanced carrier trapping in the GaNAs QW. Under resonant excitation of the GaNAs QWs, only a broad ODCR signal can be observed, corresponding to an effective mass value of 0.12m0 and 0.19m0 when the N composition is about 1.2 and 2%, respectively. This is attributed to the electron CR in the GaNAs QW with a lower electron mobility. This sizeable increase in the electron effective mass is in agreement with earlier theoretical predictions.