Type I band alignment in the ${\mathrm{GaN}}_x{\mathrm{As}}_{1-x}/\mathrm{GaAs}$ quantum wells

Three independent experimental techniques, namely, time-resolved photoluminescence (PL) spectroscopy, PL polarization, and optically detected cyclotron resonance, are employed to determine the band alignment of ${\mathrm{GaN}}_x{\mathrm{As}}_{1-x}/\mathrm{GaAs}$ quantum structures with a low-N composition. It is concluded that band lineup is type I based on the following experimental results: (i) comparable radiative decay time of the GaNAs-related emission measured from single GaNAs epilayers and from GaNAs/GaAs quantum well (QW) structures; (ii) polarization of the GaNAs-related emission; and (iii) spatial confinement of the photoexcited holes within the GaNAs layers under resonant excitation of the GaNAs QW’s.