X-Ray Diffraction Measurements on Lattice Mismatch of InTlAs Grown on InAs Substrates

InTlAs layers were grown by molecular-beam epitaxy on InAs(001) substrates, and their lattice mismatch to the substrate was characterized by X-ray diffraction measurements. In each X-ray rocking curve, a distinct peak of InTlAs was observed at a higher diffraction angle than the substrate peak, indicating a smaller lattice constant of InTlAs than InAs. The lattice mismatch, δ=(aepi-asub)/asub, was estimated to be -0.08% for a sample whose thallium composition x of In1-xTlxAs was determined to be 0.12(±0.02)% by Rutherford backscattering spectrometry.