Fluorescence EXAFS study on local structures around Bi atoms in InAs1-xBixgrown by low-pressure MOVPE

We have investigated local structures around Bi in metalorganic-vapor-phase epitaxy (MOVPE)-grown InAs1-xBix (x=0.007, 0.016 and 0.028) by fluorescenc e extended X-ray absorption fine structure (EXAFS). The EXAFS analysis reve aled that even in higher-Bi-concentration InAs1-xBix (x=0.028) the majority of Bi atoms substituted the As sites in the zincblende-type InAs lattice. Obtained Bi-In bond length was 2.81-2.82 Angstrom, which was 7% longer than the In-As bond length (2.623 Angstrom) in the InAs bulk. Such a long Bi-In bond causes local distortion in the InAs lattice and hence disorder. The d egree of the distortion and disorder was observed to increase with the Bi c oncentration.