Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240-350 nm emission

C. Himwas (1) , M. den Hertog (2) , Le Si Dang (1) , E. Monroy (3) , R. Songmuang (3)

1 NEEL - NPSC - Nanophysique et Semiconducteurs
2 NEEL - MRS - Matériaux, Rayonnements, Structure
3 NPSC - Nanophysique et Semiconducteurs

The AlGa intermixing at Al(Ga)N/GaN interfaces in nanowires and the chemical inhomogeneity in Al x Ga 1-x N/AlN nanodisks (NDs) are attributed to the strain relaxation process. This interpretation is supported by the three-dimensional strain distribution calculated by minimizing the elastic energy in the structure. The alloy inhomogeneity increases with Al content, leading to enhanced carrier localization signatures in their optical characteristics i.e. red shift of the emission, s-shaped temperature dependence and linewidth broadening. Despite these alloy fluctuations, the emission energy of AlGaN/AlN NDs can be tuned in the 240-350 nm range with internal quantum efficiencies around 30%.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

C. Himwas, M. den Hertog, Le Si Dang, E. Monroy, R. Songmuang. Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240-350 nm emission. Applied Physics Letters, 2014, 105 (24), pp.241908. ⟨10.1063/1.4904989⟩. ⟨hal-01431035⟩