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

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 mapping 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.