Impact of carrier localization on the photoluminescence characteristics of (Ga,In)(N,As) and (Ga,In)(N,As,Sb) quantum wells

Abstract

Effects of tensile, compressive, and zero strain on localized states in AlInGaN/InGaN quantum-well structuresUsing photoluminescence ͑PL͒ spectroscopy, we carry out a comparative study of the optical properties of ͑Ga,In͒͑N,As͒ and ͑Ga,In͒͑N,As,Sb͒ quantum wells. The incorporation of Sb into ͑Ga,In͒͑N,As͒ results in a reduced quantum efficiency at low temperatures but an improved one at room temperature ͑RT͒. A PL line shape analysis as well as the temperature dependence of the PL peak energy reveals the existence of band-tail localized states in both material systems. The carrier localization energy is larger for ͑Ga,In͒͑N,As,Sb͒ than for ͑Ga,In͒͑N,As͒, leading to a longer radiative lifetime and thus a reduced quantum efficiency at low temperatures for the former material. The thermal quenching of the quantum efficiency is analyzed by a rate equation model, which shows that the density of nonradiative centers is reduced in ͑Ga,In͒͑N,As,Sb͒ resulting in an enhanced quantum efficiency at RT.

Ultrafast gain and refractive index dynamics in GaInNAsSb semiconductor optical amplifiers

“…However, in cw the onset of lattice heating effects diminishes the overall blueshift. Ishikawa et al 10 reported a similar blueshift for an InGaAsNSb sample. The shift is attributed to the existence of band-tail localized states in the material and their increasing occupation by bound excitons.…”

Assessing the Nature of the Distribution of Localised States in Bulk GaAsBi

“…On the other hand, there is evidence that suggests a Gaussian distribution of localised states extending from the mobility edge may better describe the LDOS in GaAsBi 27,33 . Given that the luminescence lineshape reflects the profile of the density of states in the vicinity of the band-edge, its nature can be investigated by examining the PL spectra under different excitation conditions 48,49 . If at a certain generation rate it is assumed that the emission is dominated by excitons recombining from energy levels up to some maximum, E Max , of the LDOS distribution, and that emission at each of these energy levels can be described with a Gaussian profile, the effective luminescence intensity can be described by;where E 0 defines the centre energy of emission from each energy state in the LDOS distribution up to E Max and E Mob defines the position of the mobility edge, below which the density of states is described by g LDOS .…”

Charge separation and temperature-induced carrier migration in Ga1−xInxNNuytten1, Hayne2, Bansal3 et al. 2011Phys. Rev. B

“…[11][12][13]18,19 The signal becomes increasingly Gaussian at higher excitation powers, indicating that the localized recombination centers tend to saturate at higher excitation power densities. 20,21 Figure 2 depicts the PL energy over six orders of magnitude of excitation power density. The blueshift mentioned above is clearly present.…”