Enhanced room temperature electronic and thermoelectric properties of the dilute bismuthide InGaBiAs

We report room temperature electronic and thermoelectric properties of Si-doped In0.52Ga0.48BiyAs1-y with varying Bi concentrations. These films were grown epitaxially on a semi-insulating InP substrate by molecular beam epitaxy. We show that low Bi concentrations are optimal in improving the conductivity, Seebeck coefficient, and thermoelectric power factor, possibly due to the surfactant effects of bismuth. We observed a reduction in thermal conductivity with increasing Bi concentration, which is expected because of alloy scattering. We report a peak ZT of 0.23 at 300 K. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4761996]