Photoluminescence emission in the red band at low temperatures in type-island layers of the Al_0.32Ga_0.68 As/Al_0.29Ga_0.71As/GaAs structure obtained via liquid phase epitaxy, and its description by the mechanism of Stranski-Krastanov growth

Type-island layers for the Al_0.32Ga_0.68 As/Al_0.29Ga_0.71As/GaAs structure were grown on GaAs substrates at 600 °C, via liquid phase epitaxy with a growth rate of 0.5 °C/min for 4 min. Air leaks, as well as severe temperature gradients across the graphite sliding boat, were related to the discontinuous growth (type-island). On the other hand, the mechanism of Stranski-Krastanov growth was used to describe the growth of the type-island layers. High-resolution x-ray diffraction showed a minimal lattice mismatch between layers and substrate with a value of 0.0371%. Scanning electron microscopy showed a type-island rectangular shape with a size of 2.059 μm in width and 3.586 μm in large, with an average thickness of 291 nm. Photoluminescence studies at low temperature and room temperature demonstrated energy emission located in the red band at 1.76 eV (703 nm), which was related to free-to-bound and donor-acceptor transitions. I–V measurements for the Al_0.32Ga_0.68As/Al_0.29Ga_0.71As/GaAs structure showed the typical curve for light emitting diode, with a threshold voltage of 0.429 V.