Synthesis and properties of InxAlyGa1–x–yPzAs1–z/GaAs heterostructures

Abstract

Phase equilibria in the In–Al–Ga–P–As system have been analyzed in terms of a simple solution model. We have calculated the stability limits of InAlGaPAs solid solutions on GaAs substrates in the temperature range 937–1223 K. The addition of indium to AlGaPAs solid solutions leads to a slight decrease in growth rate under diffusion control and a considerable increase under kinetic control. Moreover, the addition of indium to AlGaPAs solid solutions has been shown to reduce the full width at half maximum of their X-ray rocking curves and photoluminescence spectra and increase the photoluminescence intensity. Increasing the indium concentration in In_xAl_yGa_1–x–yP_zAs_1–z solid solutions to x > 0.3 extends their stability region, increases their band gap, and reduces the composition region of lattice-matched In_xAl_yGa_1–x–yP_zAs_1–z/GaAs heterostructures, but these become thermal expansion-matched. With increasing indium concentration in the solid solutions, the distribution coefficients of P and As decrease, whereas those of Al and In increase.