1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Resonant depletion of photogenerated carriers in InGaAs/GaAs nanowire mats
Rent:
Rent this article for
USD
10.1063/1.4803476
/content/aip/journal/apl/102/17/10.1063/1.4803476
http://aip.metastore.ingenta.com/content/aip/journal/apl/102/17/10.1063/1.4803476
View: Figures

Figures

Image of FIG. 1.
FIG. 1.

(a) SEM image of a single In1− x Ga x As/GaAs NW (x < 0.04) deposited on a Si substrate. (b) μ-PL map of the same NW, whose SEM image is displayed in part (a). The false color scale indicates the energy of the most intense peak of the μ-PL spectra recorded on different points of the NW, as coded by the legend reported. (c) The bottom and top traces are the μ-PL spectra recorded at the NW base and tip, respectively, as indicated by the horizontal arrows. The inset sketches the NW structure made of a base, where the InGaAs core (red/light gray) is surrounded by a GaAs shell (blue/dark gray), and a tip formed by pure GaAs. The spectra were recorded in backscattering geometry, with laser and luminescence collection directions parallel to each other and both orthogonal to the wire axis (the usual symbols for vector directions have been reported in the figure).

Image of FIG. 2.
FIG. 2.

(a) PL (dashed line) and PLE (solid line) spectra of an In1− x Ga x As/GaAs NW mat (x < 0.04), whose μ-PL spectra for a singled out NW are shown in Fig. 1(c) . The narrow intense peaks labeled by A in the PL and PLE spectra correspond to the free exciton line of the GaAs tip. The enlarged view around resonance A in the inset shows a very small Stokes shift. The PL lines at about 1.46 eV are due to carrier recombination in the InGaAs section. The PLE spectrum (whose detection energy is set very close to the main GaAs shell emission, E det = 1.522 eV) displays another strong resonance B at 1.632 eV involving a higher energy critical point of the GaAs tip, see Ref. 11 . (b) Same PL (dashed line) as in (a). The PLE spectrum (solid line) was obtained by setting E det at the InGaAs emission peak (1.458 eV). At variance with part (a), antiresonances are observed for exciting photons having energies equal to those of peaks A and B in part (a); see also top right inset. All spectra were recorded in backscattering geometry (laser and luminescence collection directions parallel to each other and to the wire axis) as depicted in the bottom sketch in panel (b).

Image of FIG. 3.
FIG. 3.

(a) PL (dashed line) and PLE (solid line) spectra of an In1− x Ga x As/GaAs NW mat (x = 0.10). The PL spectrum shows two main emissions due to the GaAs (1.523 eV) and the InGaAs (1.35 eV) segments. The PLE spectra were recorded by setting the detection energy, E det, at the InGaAs energy (black line) and the GaAs energy (gray line). The inset highlights the opposite character of PLE around A peak upon changing E det. (b) Same as for (a) with x = 0.30. The PL band centered at ∼1.47 eV is likely due to GaAs-related impurities. All spectra were recorded in backscattering geometry, with laser and luminescence collection directions parallel to each other and to the wire axis, as in Fig. 2 .

Image of FIG. 4.
FIG. 4.

(a) PL (dashed line) and PLE (solid line) spectra of an In1− x Ga x As/GaAs NW mat (x = 0.05). The PL spectrum shows two main emissions due to the GaAs tip (1.523 eV) and InGaAs core (∼1.44 eV). The PLE spectrum was recorded at the InGaAs peak energy. The same ladder of levels is observed as for the other samples. The inset shows a top view SEM image of the NW ensemble. The spectra were recorded in backscattering geometry, with laser and luminescence collection directions parallel each other and to the wire axis, as in Fig. 2 . (b) Same as for (a) for NWs transferred on a Si substrate, as shown in the SEM top view image in the inset. The spectra were recorded in a backscattering geometry with laser direction and luminescence collection direction parallel to each other and both orthogonal to the wire axis (the usual symbols for vector directions have been reported in the figure).

Image of FIG. 5.
FIG. 5.

PL (dashed line) and PLE (solid line) spectra of an In1− x Ga x As/GaAs NW mat (x = 0.04) with low areal density σ = 1.5 NW/μm2; see SEM top view in the upper right panel. The PL spectrum shows a broad intense emission at 1.465 eV due to carrier recombination in the NW core. A weaker, narrow peak due to the GaAs shell can be observed at 1.523 eV. The PLE spectrum shows a broad not well defined resonance at ∼1.63 eV (B). An anti-resonance at 1.523 eV is instead observed for transition A. The spectra were recorded in backscattering geometry, with laser and luminescence collection directions parallel to each other and to the wire axis (the usual symbols for vector directions have been reported in the figure). The top left sketch depicts the path of a light ray impinging on the NW array in this backscattering geometry for different NW densities (light and dark gray indicates InGaAs and GaAs sections, respectively). According to this model, a larger part of the incident light reaches the InGaAs core for sparser NW arrays.

Loading

Article metrics loading...

/content/aip/journal/apl/102/17/10.1063/1.4803476
2013-04-29
2014-04-25
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Resonant depletion of photogenerated carriers in InGaAs/GaAs nanowire mats
http://aip.metastore.ingenta.com/content/aip/journal/apl/102/17/10.1063/1.4803476
10.1063/1.4803476
SEARCH_EXPAND_ITEM