GaAs/GaNAs core-multishell nanowires with nitrogen composition exceeding 2%

Abstract

We report the growth of GaAs/GaNAs/GaAs core-multishell nanowires having N compositions exceeding 2%. The structures were grown by plasma-assisted molecular beam epitaxy using constituent Ga-induced vapor-liquid-solid growth on Si(111) substrates. The GaNAs shell nominally contains 0%, 2%, and 3% nitrogen. The axial cross-sectional scanning transmission electron microscopy measurements confirm the existence of core-multishell structure. The room temperature micro-photoluminescence measurements reveal a red-shift of the detected emission with increasing N content in the nanowires, consistent with the expected changes in the GaNAs bandgap energy due to the bowing effect.

Near-Infrared Lasing at 1 μm from a Dilute-Nitride-Based Multishell Nanowire

“…The crystalline structure of the NWs is dominated by the zinc-blende phase (∼80%) but has inclusions of the wurtzite phase (∼20%). Further details on the growth method and structural quality of the NWs can be found in ref .…”

Effects of thermal annealing on localization and strain in core/multishell GaAs/GaNAs/GaAs nanowires

“…www.nature.com/scientificreports www.nature.com/scientificreports/ additional thin layer with a low N content due to the specifics of the growth process 49 . After the annealing Δ is reduced to Δ = 12 meV, reflecting partial strain relaxation, likely due to the formation of strain-relaxing defects.…”

“…This N composition represents the maximum reported value for NWs with good optical quality 48 . Details of the growth process can be found in 49 . The NW arrays are found to be dense and uniform, with most of the wires (3-5 μm long) standing vertically or slightly tilted from the vertical axis.…”

“…The STEM measurements also revealed the formation of an extra GaNAs layer with a small N content of 0.3-0.5%. This thin and optically inactive layer is located close to the edge of the GaAs core and is likely formed due to the active nitrogen penetrating the closed shutter of the plasma [49][50][51] . After the growth, the sample was split in several pieces and some pieces were annealed for 15 minutes in the growth chamber under As 2 overpressure at 680 °C.…”

Outermost AlGaOxnative oxide as a protection layer for GaAs/AlGaAs core-multishell nanowires

“…EDS elemental distributions suggest the formation of a layered core-multishell structure. 32,35 The NW consists of a regular hexagonal GaAs core (90 nm diameter) enclosed by an Al0.2Ga0.8As shell (10 nm thick), a GaAs cap (10 nm thick), and an Al0.1Ga0.9O outer shell (10 nm thick), as targeted by the growth protocol. The outer shell contains low As concentration but a significant concentration of Al and O, which indicates that leaving the sample exposed to the ambient air suffices to oxidize the outer Al-rich Al0.9Ga0.1As shell.…”