Magnesium-doped In0.5Ga0.5P growth by liquid-phase epitaxy

Abstract

The structural, electrical, and optical properties of Mg-doped In0.5Ga0.5P liquid-phase epitaxial layers, which were grown on (100) Cr-doped semi-insulating GaAs substrates with a supercooling method at 750 °C growth temperature, are reported. It has been found that the lattice mismatch between In0.5Ga0.5P epilayers and GaAs substrates are slightly increased with increasing Mg impurity concentration. The electrical properties of these epilayers were determined by Hall measurements in the temperature range between 77 and 300 K. The data show that both the room-temperature carrier concentration and the hole mobility of Mg-doped layers varied linearly from 3.5×1017 to 1.2×1019 cm−3 and from 50.5 to 15 cm2/V s, respectively, as a function of Mg dopant mole fraction from 1.0×10−4 to 1.5×10−3. The Mg acceptor ionization energy was evaluated as 21.3 meV. The photoluminescence results indicate that the Mg acceptor ionization energy in In0.5Ga0.5P is approximately 28–35 meV, which is different from the electrically determined value and is discussed in this report. The distribution coefficient is also determined in this report as a value of 0.12 for Mg in In0.5Ga0.5P liquid-phase epitaxy at 750 °C growth temperature.