Orientation dependent growth and luminescence of selective GaAs-Sn LPE

Abstract

Heavily Sn doped selective structures were grown by GaAs liquid phase epitaxy (LPE) both into circular holes and into 〈011〉 orientated stripes. An orientation dependent edge overgrowth of the original etched hole with the preferred directions 〈100〉, 〈111〉 and 〈110〉 was observed. It is shown that the kinetic processes, becoming visible with selective epitaxy only, are compatible with the well known diffusion controlled growth in the case of layer growth. An epitaxial mesa structure with completely smooth surfaces suitable for practical applications is reported. Scanning photo- and cathodo-luminescence measurements were carried out. A luminescence intensify profile influenced by the different preferred directions was found. The different luminescence intensities are interpreted as being caused by different doping concentrations. This interpretation is confirmed by the peak energy position and the half-width of luminescence bands. A donor concentration ratio of N D100: N D111: N D110≌1:0.85:0.7 has been found.