Crystalline Truncated Micropyramids Grown from GaAs Liquid Phase on GaP (001) Substrates

Herein, a report on the growth of crystalline truncated pyramid microstructures by liquid-phase epitaxy of Ga–As liquid phase on GaP (001) substrates under nonequilibrium (NEQ) conditions with different contact times and growth temperatures is provided. The micropyramids (MPs) have rectangular bases which are between 5 and 10 μm long, with the long sides aligned with the [110] direction. Remarkably, the results show that the growth rates of the MP under NEQ are very high compared with those of traditional epitaxial layers grown under near-equilibrium conditions. Spatially resolved microphotoluminescence mappings reveal a spatial dependence of the near-band edge emission in both wavelength and intensity within a single MP. The measured emission-wavelength range corresponds to ternary GaAs1–xPx alloys, which attests to the diffusion of P atoms from the substrate into the MPs during growth. The content of P atoms in the MPs is confirmed by spatially resolved energy-dispersive X-ray spectroscopy. Both studies show that the concentration of P is higher in the {111} planes than in the rest of the MP. A thermodynamic argument is proposed to support the experimental findings. © 2020 Wiley-VCH GmbH

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