Room temperature PL spectra of the GaInNAs QWs grown with high (dashed solid line) and low (black solid line) ion densities. The latter shows an improvement of PL intensity by a factor of 4.
Low temperature (12 K) CL mappings of the GaInNAs QWs grown with a high (a) and low (b) ion densities. The detection energies were 0.933 and 0.943 eV, respectively, which corresponds to the high-energy flank of the respective CL spectra.
Line scans of the low temperature (12 K) CL intensity of the GaInNAs QWs grown with a high (dashed line) and low (solid line) ion density. The detection energies were 0.933 and 0.943 eV, respectively.
AFM images of the GaInNAs epilayers, grown with a high [(a),(c)] and a low [(b),(d)] ion density. (a) and (b) scans are with a vertical scale of 3 nm. (c) and (d) scans are with a vertical scale of 5 nm.
(a) Surface line profiles of the GaInNAs epilayers, measured by AFM. The dashed (solid) line shows the epilayer grown with a high (low) ion density. (b) Fast-Fourier transform of the average of several cross-sectional profiles of the epilayers grown with a high (filled squares) and a low (hollow circles) ion density. Lines are interpolations between data points.
Cross-sectional TEM image of the GaInNAs QWs grown without (a) and with (b) a deflecting magnetic field to reduce ion density, taken with diffraction vector (002), which is sensitive to the composition of the layer. The insets show in more detail the microstructure of the QWs. The black and white arrows indicate the compositional fluctuations and the growth direction, respectively.
High-resolution TEM picture of the GaInNAs QW grown with reduced ion density. Upper and lower interfaces are indistinguishable.
(a) Temperature dependence of the PL peak energy for the sample grown with high (filled squares) and low (hollow circles) ion densities. Solid and dashed lines are -spline interpolations drawn as a guide for the eye. Dash-dot lines are fittings to the experimental data using Varshni model. (b) Temperature dependence of the PL FWHM from the GaInNAs QWs with high (filled squares) and low (hollow circles) ion densities. Solid and dashed lines are interpolations drawn as a guide for the eye.
Article metrics loading...
Full text loading...