The two-step growth method including growing the buffer layer on the substrate at a low-temperature and followed by growing the epitaxial layer at a high-temperature

was applied to grow high-quality InAs

0.9

Sb

0.1

on (100) GaAs substrate by LP-MOCVD. The thickness of the buffer layer and the epitaxial layer are 30 nm and 0.7 μm

respectively.The composition and crystalline quality of InAsSb were examined by means of X-ray diffraction technique

the surface morphology of the epitaxial layers was observed by scanning electron microscopy (SEM) and the electrical property of samples was measured by Hall measurements using the Van Der Pauw method. The optical properties were examined by Raman scattering measurements. The effect of the growth temperatures of both the buffer layer and the epitaxial layer on the surface morphology of the epitaxial layer has been studied. The surface morphology was found to be essentially dependent on the growth temperatures of both the buffer layer and the epitaxial layer. Generally speaking

growing a buf-fer layer between the substrate and the epitaxial layer can decrease effectively the misfit dislocations generated by the lattice mismatch between them. The experiment shows that the epitaxial layer has poor crystalline quality if the growth temperature of the buffer layer is higher. A possible explanation is the buffer lattice grown at higher temperature would become too perfect to relax stress. As a result

the misfit dislocation was extend to the epitaxial layer and formed the poor surface morphology

but the buffer layer grown at the lower temperature can decrease effectively the misfit dislocations generated by the lattice mismatch between the substrate layer and the epitaxial layer. Finally

the optimum growth temperature of the buffer layer was range from 430℃ to 450℃. In the other side

the surface morphology would become poor for the epitaxial layer at higher growth temperature. The optimum growth temperature of the epitaxial layer should be selected between 480℃ to 500℃. The high quality InAs

0.9

Sb

0.1

epitaxial layer with mirror-like surface

carrier concentrations of 1.9×10

17

cm

-3

and mobility of 6214 cm

2

/V·s has been obtained. The results of Raman scattering at room temperature showed that InAs

0.9

Sb

0.1

have a two-mode behavior. The InAs-like(LO)peak at 233cm

-1

and InSb-like(LO)peak at 187cm

-1

could be observed for InAs

0.9

Sb

0.1

. At the same times

both InAs (TO) peak at 215cm

-1

and disorder-activated longitudinal acoustic (DALA) phonons peak at 135cm

-1

were also observed.