Control of ordering in Ga0.5In0.5P using growth temperature

Abstract

The kinetic processes leading to ordering in Ga0.52In0.48P have been studied by observing the effects of substrate misorientation (0°–9°), growth rate (0.1–0.5 μm/h), and substrate temperature (570–670 °C) during growth. The ordered structure and degree of ordering are determined using transmission electron microscopy and photoluminescence (PL) spectroscopy. Low growth rates were used for samples with misorientations of 0°–9° toward the [1̄10] lattice direction to elucidate the ordering mechanism; however, due to the long times required to grow layers thick enough for PL characterization (≊1 μm), at a temperature of 670 °C the samples became less ordered with increasing misorientation angle. This was attributed to a disordering annealing process occurring during growth which leads to disorder. In order to reduce the rate of this annealing process, the growth temperature was reduced from 670 to 570 °C. At this temperature, a growth rate of 0.5 μm/h produces material with an increasing degree of order as the angle of substrate misorientation is increased from 0° to 9°. This shows that the kinetics of the ordering process are assisted by an increasing density of [110] steps on the surface.