Cross-sectional SEM image of GaAs-AlInP core-shell nanowires. Scale bar is 1 μm.
HAADF image of microtomed cross-section of GaAs-AlInP core-shell nanowire showing GaAs core (bright contrast) and AlInP shell (dark contrast). Superimposed EDS linescans indicate the presence of Ga (green) and As (light blue) coinciding with the bright core, and Al (red), In (dark blue), and P (yellow) coinciding with the darker shell, confirming the GaAs-AlInP core-shell structure. Scale bar is 20 nm.
Model J-V characteristics (thin solid lines for forward bias, thin dashed lines for reverse bias) superimposed on the measured data (fb = forward bias, circles; rb = reverse bias, crosses) for unpassivated and passivated nanowires. (a) Dependence of forward bias model (thin solid lines) on surface trap density D without bulk or surface recombination (τ = ∞, S = 0). (b) Forward bias J-V model (thin solid lines) using D = 3 × 1012 cm−2 and S = 1.8 × 104 cm s−1 for unpassivated nanowires, and D = 9 × 1011 cm−2 and S = 5400 cm s−1 for passivated nanowires.
Electron concentration n (solid lines) and hole concentration p (dashed lines) versus radial position r across an unpassivated nanowire for applied forward bias of 0, 0.25, 0.50, 0.75, and 1 V (bottom to top). The radial cross-section was taken at the mid-point along the nanowire length. ro is the nanowire radius of 26 nm.
Electric potential ψ along the axis of an unpassivated nanowire for forward bias of 0, 0.25, 0.50, 0.75, and 1 V. The vertical dashed line located at 0 μm indicates the presence of a potential barrier at the interface between the base of the nanowire on the right and the underlying substrate on the left. The nanowire top is located at position 1 μm. Inset: the electric potential distribution in the nanowire at a forward bias of 1 V (color scale is in volts). The horizontal scale is along the nanowire radius (=26 nm) and the vertical scale is along the nanowire axis (length = 1 μm). The horizontal and vertical scales are not equal.
Photoluminescence spectra from unpassivated and passivated nanowires.
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