Photoluminescence properties of localized states caused by nitrogen alloying in a GaInNAs/GaAs single quantum well

Optical properties of GaInNAs quantum wells on misoriented substrates grown by MOVPE

“…The longer decay time corresponds to the larger localization of carriers in the band-tail region. The PL-decay profiles exhibit nonexponential type, which can be explained by a stretched exponential form peculiar to the disordered systems [8,9]. offset angle and UDMH flow in this case.…”

“…According to Refs. [8,9], random fluctuations of nitrogen atoms with large electron affinity in GaInNAs cause the disorder of the band-edge state and the carrier localization. Since an increase in the offset angle leads to an increase in a the density of steps of the lattice plane, the random fluctuation of the alloy potential seems to be enhanced in the highly-misoriented substrate.…”

“…We also measured PR spectra: see Refs. [8,9] for details of the measurement. It is obvious that the PL-peak wavelength becomes longer with the increasing offset angle from 21 to 151 : The difference of the PL-peak wavelengths in 21 and 151 is about 60 nm.…”

“…It is obvious that the PL-peak wavelength becomes longer with the increasing offset angle from 21 to 151 : The difference of the PL-peak wavelengths in 21 and 151 is about 60 nm. Since the carrier localization is negligible at room temperature [9], the PL-peak wavelength corresponds to the band-edge energy. Namely, the band-edge energy is lowered by the increase in the offset angle, which suggests that the incorporation efficiency of N is enhanced.…”

“…However, it is difficult to obtain highquality GaInNAs QW grown by metalorganic vapor phase epitaxy (MOVPE) using 1,1-dimethylhydrazine (UDMH) as a nitrogen (N) precursor owing to a low efficiency of incorporation of N into GaInNAs [4]. Moreover, the incorporation of N usually produces localized states, socalled band-tail states, in GaInNAs/GaAs QWs since N has large electron affinity [5][6][7][8][9]. In order to improve the optical properties of Ga(In)NAs/GaAs QWs, Moto et al reported that a change of surface orientation of a substrate is one of strategies [10,11].…”