Wd. Huang et al., AlSb compositional nonuniformity induced by different Ga-Al exchange modesin the melt growth of AlxGa1-xSb, JPN J A P 1, 40(7), 2001, pp. 4648-4651
The AlSb compositional nonuniformity in a melt grown AlxGa1-xSb crystal aro
und the macrostep and the boundary between the facet and off-facet was meas
ured using a spatially resolved photoluminescence (SRPL) technique. It was
found that the AlSb composition is higher in the riser part of a macrostep
than in the terrace part. It was also found that in the riser part the AlSb
composition increases continuously as the step density increases. In the f
acet/off-facet transition region, it is shown that the AlSb composition in
the off-facet area is 13% higher than in the facet area. The experimental r
esult is explained qualitatively by assuming that the AlSb compositional no
nuniformity is induced by different degrees of Ga-Al exchange, which depend
s on the step velocity. It is concluded that even at temperatures as high a
s the melting point, the Ga-Al exchange cannot reach an equilibrium and the
incorporation of Al depends on the degree of misorientation.