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 fluorescence extended X-ray absorption fine structure (EXAFS). The EXAFS analysis revealed 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 2.81-2.82Å, which was 7% longer than the In-As bond length (2.623Å) in the InAs bulk. Such a long Bi-In bond causes local distortion in the InAs lattice and hence disorder. The degree of the distortion and disorder was observed to increase with the Bi concentration.