Despite the high density of threading dislocations generally found in (AlGaIn)N heterostructures, the light emission efficiency of such structures is exceptionally high. It has become common to attribute the high efficiency to compositional fluctuations or even phase separation in the active GaInN quantum well region. The resulting localization of charge carriers is thought to keep them from recombining nonradiatively at the defects. Here, we show that random disorder is not the key but that under suitable growth conditions hexagonal V-shaped pits decorating the defects exhibit narrow sidewall quantum wells with an effective band gap significantly larger than that of the regular c-plane quantum wells. Thereby nature provides a unique, hitherto unrecognized mechanism generating a potential landscape which effectively screens the defects themselves by providing an energy barrier around every defect.
Highly efficient gas‐diffusion barriers based on nanolaminates of alternating Al2O3 and ZrO2 layers grown at 80 °C by atomic‐layer deposition are presented. Ultralow water‐vapor permeation rates are reported, and a dramatic reduction of statistical defects on larger areas was found compared to single Al2O3 layers. This study provides a concept for the encapsulation of organic optoelectronic devices.
Articles you may be interested inSelf-assembled monolayer cleaning methods: Towards fabrication of clean high-temperature superconductor nanostructures Appl. Phys. Lett. 86, 154104 (2005); 10.1063/1.1899753
Electrode modification by electron-induced patterning of self-assembled monolayersWe show the fabrication of gold nanostructures using self-assembled monolayers of aliphatic and aromatic thiols as positive and negative electron beam resists. We applied a simple and versatile proximity printing technique using focused ion beam structured stencil masks and low energy ͑300 eV͒ electrons. We also used conventional e-beam lithography with a beam energy of 2.5 keV and doses from 3500 to 80 000 C/cm 2 . Gold patterns were generated by wet etching in KCN/KOH and characterized by atomic force microscopy and scanning electron microscopy. The width of the finest lines is ϳ20 nm; their edge definition is limited by the isotropic etching process in the polycrystalline gold.
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