Structural and compositional analysis of InBixAsySb(1−x−y) films grown on GaAs(0 0 1) substrates by liquid phase epitaxy

The growth of epitaxial $InBi_xAs_ySb_(1-x-y)$ layers on highly lattice mis-matched semi-insulating GaAs substrates has been successfully achieved via the traditional liquid phase epitaxy. Orientation and single crystalline nature of the film have been confirmed by X-ray diffraction. Scanning electron micrograph shows abrupt interface at micrometer resolution. Surface composition of Bi(x) and As(y) in the $InBixAsySb_(1-x-y)$ film was measured using energy dispersive X-ray analysis and found to be 2.5 and 10.5 at.%, respectively, and was further confirmed with X-ray photoelectron spectroscopy. Variation of the composition with depth of the film was studied by removing the layers with low current (20 μA) $Ar^+$ etching. It was observed that with successive Ar+ etching, In/Sb ratio remained the same, while the As/Sb and Bi/Sb ratios changed slightly with etching time. However after about 5 min etching the As/Sb and Bi/Sb ratios reached constant values. The room temperature band gap of $InBi_0.025As_0.105Sb_0.870$ was found to be in the range of 0.113–0.120 eV. The measured values of mobility and carrier density at room temperature are $3.1 \times 10^4 cm^2 V^-1 s^-1$ and $8.07 \times 10¹⁶ cm^-3$, respectively.