Properties of low-temperature grown InAs and their changes upon annealing

As-grown and annealed samples of InAs layers grown by MBE at 150-350℃ were characterized by electron probe microanalysis (EPMA), high resolution X-ray diffraction (HRXRD), Hall measurements, and secondary ion mass spectrometry (SIMS). EPMA revealed that the As mole fractions in the layers grown at 150-200 ℃ are higher by about 0.5 % than those in the layers grown at 300-350 ℃. HRXRD measurements revealed that the layers grown at 150-200 ℃ have larger lattice spacings than the InAs substrate by about 0.02 %. Hall measurements revealed that the free-electron concentration in the layer grown at 200 ℃ is as high as 1.4×10^<19> cm^<-3> while such a high concentration of impurities cannot be detected by SIMS. Upon annealing at higher temperatures than 250 ℃, both the lattice spacing and the free-electron concentration of the layer grown at 200 ℃ were observed to decrease. These phenomena can be reasonably attributed to antisite As.