Impact of thermal treatments on epitaxial Ga_yIn_1−yAs_1−xBi _x layers luminescent properties

Abstract

In this work, thick Ga_0.485In_0.515As_1−xBi _x epitaxial layers were grown on semi-insulating (100)-oriented InP:Fe substrates by molecular beam epitaxy. For investigation of the buffer layer influence on Ga_0.485In_0.515As_1−xBi _x properties, two compositions of buffers were used: lattice matched to InP:Fe substrate—Ga_0.477In_0.523As, and lattice matched to bismide layer—Ga_0.434In_0.566As. The buffer layer thickness varied from 100 to 650 nm. Three hundred-nm-thick bismide layers were grown at 280–300 °C substrate temperature with growth rate of 300 nm/h. Structural investigations of ω − 2θ rocking curves measured for (004) reflex revealed the incorporation of Bi up to 3.6% in quaternary compound. Bismide layer surface inspection by atomic force microscopy demonstrated roughness of about 0.65 nm. Despite the fact that structures are 100’s of nanometers thick, reciprocal space map** measurement demonstrated that both the buffer and the bismide layers are fully strained. It has also been revealed that rapid annealing at the temperature range of 550–700 °C of Ga_0.485In_0.515As_1−xBi _x layers improves photoluminescence intensity, extends carrier lifetime and enhances electron mobility.